SW7081009_HISTORICAL FILE_20090220

WAtZ0
NCDEENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
February 20, 2009
Mr. Robert S. Hall, Sr. Exec. Vice President
State Employees' Credit Union
1000 Wade Avenue
Raleigh, NC 27605
Subject: Stormwater Permit No. SW7081009
SECU — Swan Quarter
High Density Commercial Wet Pond Project
Dear Mr. Hall: Hyde County
The Washington Regional Office received a complete Stormwater Management
Permit Application for SECU — Swan Quarter on October 28, 2008. Staff review
of the plans and specifications has determined that the project, as proposed, will
comply with the Stormwater Regulations set forth in Session Law 2008-211 and
Title 15A NCAC 21-1.1000. We are forwarding Permit No. SW7081009 dated
February 20, 2009, for the construction of the subject project. l 13 I
2 C,a.z
This permit shall be effective from the date of issuance until February 20, 2019,
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 thirty (30) 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,
6714 Mail Service Center, Raleigh, NC 27699-6714. 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 Samir Dumpor, or me at [phone].
inc ly
,
Al H �'g
Regional upervisor
Surface Water Protection Section
North Carolina Division of Water Quality Internet: www.ncwatercualitv.ore
943 Washington Square Mall Phone: [phone] One
Washington,NC 27889 FAX [phone] NorthCa�rofiina
An Equal Opportunity/Affirmative Action Employer-50%Recycled/l0%Post Consumer Paper Nahanally

Page 2 of 2
AH/ sd: J:\WPDATA\WQS\ State SW-SD\Permits — Wet Pond\SW7081009
cc: Patty Hillburn, PLS, Pabst & Hilburn, PA
yde County Building Inspections
Washington Regional Office
Central Files

State Stormwater Management Systems
Permit No. SW7081009
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
NPDES PHASE II 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
State Employees' Credit Union
SECU— Swan Quarter
Hyde County
FOR THE
construction, operation and maintenance of two wet detention ponds in compliance with
the provisions of Session Law 2008-211 and 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 February 20, 2019, and
shall be subject to the following specified conditions and limitations:
I. DESIGN STANDARDS
1. 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 35,148 square feet of
impervious area (total for both wet ponds).
3. The tract will be limited to the amount of built-upon area indicated in Section 1.7
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.
6. The built-upon areas associated with this project shall be located at least 30 feet
landward of all perennial and intermittent surface waters.
Page 2 of 7

State Stormwater Management Systems
Permit No. SW7081009
7. The following design criteria have been provided in the wet detention ponds and
must be maintained at design condition:
Pond #1 Pond #2
a. Drainage Area, ft2: 20,467 39,006
b. Total Impervious Surfaces, ftZ: 11 ,695 23,453
C. Design Storm, inches: 1.5 1.5
d. Pond Depth, feet: 6.0 6.0
e. TSS removal efficiency: 90% 90%
f. Permanent Pool Elevation, FMSI : 2.0 2.0
9. Permanent Pool Surface Areq, ft : 2,443 3,882
h. Permitted Storage Volume, ft : 2,901 3,627
i. Temporary Storage Elevation, FM§L: 2.75 2.75
j. Predevelopment 1 year 24 hour, ft /s: 0.70 1.30
k. Post development 1 year 24 hour, W /s: 1.72 3.45
I. Controlling Orifice: 0.75"0 pipe 0.75 0 pipe
M. Permitted Forebay Volume, ft3: 996 1,429
n. Receiving Stream/River Basin: Swanquarter Bay / Tar-Pamlico
o. Stream Index Number: 29-49
P. Classification of Water Body: "SA; ORW"
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 time 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 re-vegetation of slopes and the vegetated filter strip.
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, level
spreader, filter strip, catch basins and piping.
g. Access to the outlet structure must be available at all times.
4. Records of maintenance activities must be kept for each permitted BMP. The
records will indicate the date, activity, name of person performing the work and
what actions were taken.
5. The permittee shall submit to the Division of Water Quality an annual summary
report of the maintenance inspection records for each BMP. The report shall
summarize the inspection dates, results of the inspections, and the maintenance
work performed at each inspection.
6. Access to the stormwater facilities shall be maintained via appropriate
easements at all times.
7. The facilities shall be constructed as shown on the approved plans. This permit
shall become void unless the facilities are constructed in accordance with the
conditions of this permit, the approved plans and specifications, and other
Page 3 of 7

State Stormwater Management Systems
Permit No. SW7081009
supporting data.
8. 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.
9. 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.
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 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.
12. The permittee shall submit final site layout and grading plans for any permitted
future areas shown on the approved plans, prior to construction.
13. A copy of the approved plans and specifications shall be maintained on file by
the Permittee for the life of the project.
III. GENERAL CONDITIONS
1. 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 completed Name/Ownership Change form, to the Division of Water
Quality, signed by both parties, and accompanied by supporting documentation
as listed on page 2 of the form. The project must be in good standing with the
Division. The approval of this request will be considered on its merits and may or
may not be approved.
2. The permittee is responsible for compliance with all permit conditions until such
time as the Division approves the transfer request.
3. 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
Page 4 of 7

State Stormwater Management Systems
Permit No. SW7081009
accordance with North Carolina General Statute 143-215.6A to 143-215.6C.
4. 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.
5. 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.
6. 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.
7. The permit issued shall continue in force and effect until revoked or terminated.
The permit may be modified, revoked and reissued or terminated for cause. The
filing of a request for a permit modification, revocation and re-issuance or
termination does not stay any permit condition.
8. 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.
9. Approved plans and specifications for this project are incorporated by reference
and are enforceable parts of the permit.
10. The issuance of this permit does not prohibit the Director from reopening and
modifying the permit, revoking and reissuing the permit, or terminating the permit
as allowed by the laws, rules and regulations contained in Session Law 2008-
211, Title 15A NCAC 2H.1000, and NCGS 143-215.1 et.al.
11. The permittee shall notify the Division of any name, ownership or mailing
address changes at least 30 days prior to making such changes.
12. This permit shall be effective from the date of issuance until February 16, 2019.
Application for permit renewal shall be submitted 180 days prior to the expiration
date of this permit and must be accompanied by the processing fee.
Permit issued this the 20th day of February, 2009.
7RTH AROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
for Col .n H. Sullins, Director
Division of Water Quality
By Authority of the Environmental Management Commission
Page 5 of 7

State Stormwater Management Systems
Permit No. SW7081009
SECU — Swan Quarter
Stormwater Permit No. SW7081009
Hyde County
Designer's Certification
I, , as a duly registered in the
State of North Carolina, having been authorized to observe (periodically/weekly/ full
time) the construction of the project,
(Project)
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:
SEAL
Signature
Registration Number
Date
Page 6 of 7

State Stormwater Management Systems
Permit No. SW7081009
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
Hyde County Building Inspections
Page 7 of 7

Permit Number:
(to be provided by DWQ)
Drainage Area Number:
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected,repaired or replaced immediately. These deficiencies can affect the integrity
of structures,safety of the public,and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
,JAN 2 3 2009
This system (check one):
❑ does ® does not incorporate a vegetated filter at the outlet.
This system (check one):
® does ❑ does not incorporate pretreatment other than a IForebay.
Important maintenance procedures:
— Immediately after the wet detention basin is established,the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed,until the plants become established(commonly six weeks).
— No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
— Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
— If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
— Once a year,a dam safety expert should inspect the embankment.
After the wet detention pond is established,it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potentialproblem: How I will remediate theproblem:
The entire BMP Trash debris is present. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully,and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. I approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4

Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potentialproblem: How I will remediate theproblem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage, dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds,preferably by
hand. If pesticide is used,wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead,diseased or Determine the source of the
dying. problem: soils,hydrology,disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds,preferably by
hand. If pesticide is used,wipe it on
the plants rather than spraying,
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth,
Cattails,phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide(do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4

Permit Number:
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potentialproblem: How I will remediate theproblem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present, consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office,or
outlet. the 401 Oversight Unit at 919-733-
1786.
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 5.00 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 2.00 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 2.00
Sediment Removal .0.00 Pe manen Pool
-------------- Volume Sediment Removal Elevation-3.00 Bottom Elevatioi -1.00 -ft Min. --------------------------- '-----'----Ivolume
-----
Sediment Bottom Elevation-4.00 1-ft n.
Storage Sediment
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4

Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:State Employees' Credit Union- Swan Quarter
BMP drainage area number: Pond 1
Print name: Robert S. Hall
Title: Sr. Executive Vice President
Address: 1000 Wade Avenue- Raleigh,NC 27605
Phone: [phone] A In
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.
I, ` O-/ `C -b (��� , a Notary Public for the State of
J �h CWotttvq County of�JOhN do hereby certify that
CL U
q personally appeared before me this
�� St
day of �A�yAf'� — I , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
Jcw,c 1b lsoacz
JAN6 �SA�CS
SEAL
My commission expires M�1 t 7D 12
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4

Permit Number:
(to be provided by DWQ)
Drainage Area Number: F6AD 9'Z
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected,repaired or replaced immediately. These deficiencies can affect the integrity
of structures,safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided. OCT 2 8 2008
This system (check one):
❑ does ® does not incorporate a vegetated filter at the outlet.
This system (check one):
® does ❑ does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed,until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance,the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year,a dam safety expert should inspect the embankment.
After the wet detention pond is established,it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches(or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potentialproblem: How I will remediate theproblem:
The entire BMP Trash/debris is present. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully,and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4

Permit Number:
(to be provided by DWQ)
Drainage Area Number: f6 ,C 'a"L.
BMP element: Potentialproblem: How I will remediate theproblem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
Swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the Swale if necessary to
Swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems,
Weeds are present. Remove the weeds,preferably by
hand. If pesticide is used,wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead,diseased or Determine the source of the
dying. problem: soils,hydrology,disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds,preferably by
hand. If pesticide is used,wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails,phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide(do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 2 of 4

Permit Number:
(to be provided by DWQ)
Drainage Area Number: Po, D 4-L_
BMP element: Potentialproblem: How I will remediate theproblem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair.
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office,or
outlet. the 401 Oversight Unit at 919-733-
1756.
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 3.00 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 2.00 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
011 in the blanks)
Permanent Pool Elevation 3.00
Sediment Removal . 1.00 Pe manes Pool
-------------- Volume Sediment Removal Elevation0.00 Volume
_ ----------------------------- ---------— -"- ---
Bottom Elevatioi 0.00 -ft Min.
Sediment BottomElevation-1.00 I-ft n.
Storage Sediment
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.3 Page 3 of 4

Permit Number:
(to be provided by DFVQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:State Employees' Credit Union - Swan Quarter
BMP drainage area number: Pond #2
Print name: Robert S. Hall
Title: Sr. Exec. Vice President
Address:1000 Wade Avenue Ralei h NC 27605
Phone:[phone]
Signature:
Date: T
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.
1, 2L) U�, POv�V), VJ�_GfZ••U _ , a Notary Public for the State of
/J C County of V J G K 2 , do hereby certify that
S , '�G �� personally appeared before me this
day of Dclt-v(De C aW� , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal, �1
`+2
9 pIJ M �V
SEAL n I q
My commission expires I �1O lI �U a
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4

20 Cs�y
DWQ USE ONLY
Date Received Fee Paid Permit Number
P009 1 15W708 1005
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):
State Emiloyees'Credit Union
2. Print Owner/Signing Official's name and title(person legally responsible for facility and compliance):
Robert S.Hall, Sr.Exec.Vice President
3. Mailing Address for person listed in item 2 above:
1000 Wade Avenue
City:Raleigh State:NC Zip:27605
Phone: (919 ) 839-5000 Fax: ( )
Email:
4. Project Name(subdivision,facility,or establishment name-should be consistent with project name on plans,
specifications,letters,operation and maintenance agreements,etc.):
State Employees'Credit Union-Swan Quarter
5. Location of Project(street address):
US Hwy 264(0.42 miles west of US Hwy 264 and SR 1166 intersection)
City:Swan Quarter County:Hyde Zip:27885
6. Directions to project(from nearest major intersection):
US Hwy 264(0.42 miles west of US Hwy 264 and SR 1166 intersection)
7. Latitude:35'25'29" N Longitude:76°19'35" W of project
8. Contact person who can answer questions about the project:
Name:Pabst&Hilburn,PA (Patty E.Hilburn) Telephone Number: (919 ) 848-4399
Email:[e-mail]
II. PERMIT INFORMATION:
1. Specify whether project is(check one): ®New [-]Renewal ❑Modification
Form SWU-101 Version 09.25.08 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 N/A and its issue date(if known)
3. Specify the type of project(check one):
❑Low Density ®High Density ❑Redevelop ❑General Permit ❑Universal SMP ❑Other
4. Additional Project Requirements (check applicable blanks;information on required state permits can be
obtained by contacting the Customer Service Center at 1-877-623-6748):
❑CAMA Major ®Sedimentation/Erosion Control ❑404/401 Permit ❑NPDES Industrial
Stormwater
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.
Post-Development runoff will be directed by grass swales to wet detention ponds as shown on plans prepared red by
Pabst&Hilburn,PA,and dated 1/16/09 Stormwater from the wet ponds will be discharged into an existing
drainage ditch located along US Hwy 264
2. Stormwater runoff from this project drains to the Tar-Pamlico River basin.
3. Total Property Area: 2.91 acres 4. Total Coastal Wetlands Area: N/A acres
5. Total Property Area(3) - Total Coastal Wetlands Area(4) = Total Project Area**: 2.91 acres
6. (Total Impervious Area/ Total Project Area)X 100 = Project Built Upon Area(BUA): 27.7 %
7. How many drainage areas does the project have? 2
8. 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.
For high density projects,com lete the table with one drainage area for each engineered stormwater device.
Basin Information Drainage Area 1 Drainage Area 2
Receiving Stream Name Swan Quarter Bay Swan Quarter Bay
Stream Class&Index No. SA;ORW SA;ORW �—
Total Drainage Area(so 20,467 39,006
On-site Drainage Area (sf) 20,467 39,006
Off-site Drainage Area(so 0 0
Existing Impervious*Area(so 0 0
Proposed Impervious*Area(so 11,695 23453
% Impervious*Area(total) 57.1 60.1
Impervious*Surface Area Drainage Area 1 Drainage Area 2
On-site Buildings(sf) 4,258
On-site Streets (so
On-site Parking (so 10,421 16,221
On-site Sidewalks (so 1199 1,738
Other on-site (so 75 1,236
Off-site (so
Total (so: 11,695 23,453
hapemious area is defined as the built upon area including, but not liniited to, buildings, roads,parking areas,
sidernalks,gravel areas,etc.
Form SWU-101 Version 09.25.08 Page 2 of

**Total project area shall be calculated to exclude Coastal Wetlands from use When calculating the built upon area
percentage calculation. This is the area used to calculate overall percent project built upon area(BUA).
9. How was the off-site impervious area listed above derived? N/A
Projects in Union County: Contact the DWQ Central Ojjrce staff to check to see ifyou project is located
within a Threatened&Endangered Species watershed that may be subject to more stringent stormwater
requirements.
IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
One of the following property 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.
Forms can be downloaded from http://h2o enr state nc us/su/bmp forms htm-deed restrictions.
Form DRPC-1 High Density Commercial Subdivisions
Form DRPC-2 High Density Developments with Outparcels
Form DRPC-3 High Density Residential Subdivisions
Form DRPC-4 Low Density Commercial Subdivisions
Form DRPC-5 Low Density Residential Subdivisions
Form DRPC-6 Low Density Residential Subdivisions with Curb Outlets
By your signature below,you certify that the recorded property restrictions and protective covenants for this
project shall include all the applicable items required in the above form,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 NC DWQ 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 Permitting Unit at(919)807-6300 for the status and
availability of these forms. Forms can be downloaded from http://h2o enr state nc us/su/bmp forms limn.
Form SW401-Low Density Low Density Supplement
Form SW401-Curb Outlet System Curb Outlet System Supplement
Form SW401-Off-Site System Off-Site System Supplement
Form SW401-Wet Detention Basin Wet Detention Basin Supplement
Form SW401-Infiltration Basin Infiltration Basin Supplement
Form SW401-Infiltration Trench Underground Infiltration Trench Supplement
Form SW401-Bioretention Cell Bioretention Cell Supplement
Form SW401-Level Spreader Level Spreader/Filter Strip/Restored Riparian Buffer Supplement
Form SW401-Wetland Constructed Wetland Supplement
Form SW401-Grassed Swale Grassed Swale Supplement
Form SW401-Sand Filter Sand Filter Supplement
Form SW401-Permeable Pavement Permeable Pavement Supplement
Form SW401-Cistern Cistern Supplement
Fonn SWU-101 Version 09.25.08 Page of

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 Office. (Appropriate office may be found by locating project on the
interactive online map at http://h2o.enr.state.ne.us/su/msi maps.htm)
1. Please indicate that you have provided the following required information by initialing in the space provided
next to each item.
Init' is
• Original and one copy of the Stormwater Management Permit Application Form
• Original and one copy of the Deed Restrictions&Protective Covenants Form(if
required as per Part IV above)
• Original of the applicable Supplement Form(s)and O&M agreement(s)for each BMP
• Permit application processing fee of$505 (Express:$4,000 for HD,$2,000 for LD)
payable to NCDENR
• Calculations& detailed narrative description of stormwater treatment/management
• Copy of any applicable soils report
• Two copies of plans and specifications(sealed, signed &dated), 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
-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(such as additional information requests),please complete this section. (ex. designing engineer or firm)
Designated agent(individual or firm):Pabst& Hilburn,PA (Patty E. Hilburn,PLS)
Mailing Address:911 Paverstone Drive,Suite E
City: Raleigh State: NC Zip: 27520
Phone: (919 ) 848-4399 Fax: (919 ) 848-4395
Email:[e-mail]
VIII. APPLICANT'S CERTIFICATION
I, (print or type name of person listed in General Information, item 2) Robert S. Hall
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 2H.1000.
Signature: Date:
Form SWU-101 Version 09.25.08 Page 4 o1'4

"'oF wArFgQ Beverly Eaves Perdue,Governor
YDec Freeman,Secretary
t— North Carolina Department of Environment and Natural Resources
O ( Coleen H.Sullins,Director
Division of Water Quality
State Employees Credit Union February 13, 2009
Attn: Mr. Robert S. Hall
1000 Wade Ave. -
Raleigh, NC 27605 Subject: Stormwater Review SW7081208
SECU-Columbia
Tyrrell County
Dear Mr. Hall:
This office received a stormwater permit application for the subject project on December 22,
2008. A preliminary review of your project indicates that before a State Stormwater permit can be issued,
the following additional information is needed:
1. Wet pond design should be based on a minimum average depth of 3-feet. Revise
plans/calculations to provide minimum average depths. (BMP manual, chapter 10).
2. Soils report indicates the seasonal high water table (SHWT) at this site should be about 18-
inches below existing ground surface. Based on this info and the County Soils Report,
the SHWT elevation for this site should be between 3.5 -4.0 ft. The design permanent
pool elevations should be set within 6-inches of the SHWT; therefore, permanent pool
design elevations should be 3.5 -4.5 ft. Explain/justify design elevations.
3. Provide plan details and written vegetation plan for wet pond perimeter shelf. Wetland seed
mix is not acceptable; (BMP manual, chapters 6 & 10).
4. Small diameter orifices can easily clog; suggest revise orifice structure with minimum 4-inch
PVC pipe-capped and drilled. (See example BMP manual, chapter 10).
5. The proposed wet ponds are relatively small; suggest eliminate diversion berms to enhance
sediment storage. Also, top of forebay berms should be 6-inches below design
permanent pool elevation.
5. Revise application, supplements, narrative & plans as need to reflect changes.
The above requested information must be submitted to this office prior to March 13, 2009, or your
application will be returned as incomplete. The return of this project will necessitate resubmittal of all
required items including a new application fee. If you need additional time to complete the application
package, please mail or fax your request to this office and include any reason(s) for the time delays.
You should also be aware that the Stormwater Rules require that the permit be issued prior to
any development activity. Construction without a permit is a violation of 15A NCAC 2H.1000 and North
Carolina General Statute 143-215.1 and may result in civil penalties of up to $25,000 per day.
If you have questions, please feel free to contact me at(252) 948-3919, or you can send a message
to: [e-mail].
Sincerely,
William J. Moore
Environmental Engineer
Washington Regional Office
cc: Pabst& Hilburn, PA
Tyrrell County Planninglinspections
Washington Regional Office p
Mailing Address Phone[phone] Location N,p0,rerhCaro ina
1617 Mail Service Center Fax [phone] 512 N.Salisbury St. dvahlCaltJ
Raleigh,NC 27699-1617 Raleigh,NC 27604
Internet: www.ncwateraualitv.or¢ Customer Service 1-877-623-6748
An Equal Opportunity/Affirmative Action Employer-50%Recycled/10%Post Consumer Paper

�QF wATFino Michael F.Easley,Governor
y 7 T William G.Ross Jr,Secretary
r North Carolina Department of Environment and Natural Resources
O Y Coleen H.Sullins,Director
Division of Water Quality
December 19, 2008
Mr. RVEmoyees' Credit
all, Vice President
State Union
1000Avenue
Raleig , 27605
Subject:: Stormwater Review SW7081009
State Employees' Credit Union—Swan Quarter
Hyde County
Dear Mr. Hall:
This office received a Coastal Stormwater permit application and plans for the subject project on
October 28, 2008. A preliminary review of your project indicates that before a State Stormwater permit
can be issued the following additional information is needed:
V " The impervious area in drainage area 1 (in the SW Application) is different than the,
impervious area in the wet pond supplement and calculations. Please revise.
✓ : Revise section 11.3 of the Stormwater Application to specify the type of the project as High
✓/ Density rather than General Permit.
3. As proposed both wet ponds have the depth of 2'. Size the wet pond using the average
pond depth (use the BMP Manual for more information about this requirement) and revise
the wet pond supplements for both ponds to include these information. Please be advised
that the pond depth does not include the 1' sediment depth.
4. The two earthen berms with side slopes of 2:1 are proposed for each pond in order to
achieve the longer flow path, however these berms will reduce the available volume within
the wet pond. Please clarify if the volume taken by these berms was substracted of the total
volume within the pond
5. For the orifice calculation use the orifice formula as specified in section 3 of the BMP
/ Manual (Stormwater Calculations section).
VV6. Delineate wetlands on site or provide a note on plans that none exist.
7. Plan sheet C1201, wet pond #2, grass swale #3 is discharging into the main pond. Please
✓ revise and redirect swale to the forebay.
8. Revise the outlet structure detail to show a trash rack with 6" or less square openings (sheet
C5102).
9. On the wet pond detail show elevations for both the permanent pool and the temporary pool
(sheet C5102).
j 10. Revise all other documents to reflect above changes.
v/ 11. Provide 2 sets of signed and sealed plan sheets calculations and documents.
The above requested information must be received in this office prior to January 23, 2009 or
your application will be returned as incomplete. The return of this project will necessitate resubmittal of
all required items including the application fee. If you need additional time to submit the required
information, please mail or fax your request for time extension to me at the Letterhead address and
include the application number on the request. The request must include justification for the amount of
additional time needed. The request will only be granted for justifiable delays that are unforeseen and
beyond the owner or consultant's control.
North Carolina Division of Water Quality Internet: www ncwateraualiri ore One
943 Washington Square Mall Phone[phone] NorthCarolina
Washington,NC 27889 Fax [phone] a atur ll ff
An Equal OpportunitylAlfrmative Action Employer-50%Recycledll0%Post Consumer Paper �/ {�N% {K{I�I�

You should also be aware that the Stormwater Rules require that the permit be issued prior to
any development activity. Construction without a permit is a violation of 15A NCAC 21-1.1000 and North
Carolina General Statute 143-215.1 and may result in civil penalties of up to $25,000 per day.
Please reference the Stormwater Project Number above on all correspondence. If you have
questions, please feel free to contact me at [phone].
Sincerely,
Samir Dumpor, PE
Environmental Engineer
Washington Regional Office
cc: " Washington Regional Office
Patty Hillburn, PLS, Pabst & Hillburn, PA (911 Paverstone Drive, Suite E, Raleigh, NC 27520)

911 Paverstone Drive,Suite E
P PABST& HILBURN, PA Raleigh, NC 27615
H Office: 919.848,4399
ENGINEERING&CONSUL iING Fax: [phone]
January 19, 2009 P&H Project: 102-08
Mr. Samir Dumpor, PE
Environmental Engineer
NCDENR- Division of Water Quality ��� 3 ����
943 Washington Square Mall
Washington, NC 27889
RE: Responses to Stormwater Review Comments - SW7081009
State Employees' Credit Union - Swan Quarter
Dear Mr. Dumper:
Please find below responses to stormwater review comments dated December 19,
2009.
V1. The impervious area in drainage area 1 (in the SW Application) is different than
the impervious area in the wet pond supplement and calculations. Please revise.
P&H Response: The impervious areas have been checked and corrected in the SW
Application, the wet pond supplement, and calculations.
V//2. Revise section 11.3 of the Stormwater Application to specify the type of the
project as High Density rather than General Permit.
P&H Response: The type of project in section 11.3 has been revised to High Density
as requested.
3. As proposed both wet ponds have the depth of 2'. Size the wet pond using
VV average pond depth (use BMP Manual for more information about this
requirement) and revise the wet pond supplements for both ponds to include
these information. Please be advised that the pond depth does not include the
1' sediment depth.
P&H Response: Both wet ponds have been revised to have an average depth of 3
feet or more, which does not include the 1 foot of sediment depth. However, the
slope below the vegetated shelf is now 2:1 (approved by Samir Dumpor) in order

to achieve the 3 foot average depth without increasing the size of the ponds
further.
1/ 4. The two earthen berms with side slopes 2:1 are proposed for each pond in order
to achieve the longer flow path, however these berms will reduce the available
volume within the wet pond. Please clarify if the volume taken by these berms
was subtracted of the total volume within the pond.
P&H Response: Earthen berms have been removed and ponds have been
elongated to achieve the 3:1 flow path. See Sheet C1201 for revision.
V 5. For the orifice calculation use the orifice formula as specified in section 3 of the
BMP Manual (Stormwater Calculations section).
P&H Response: Orifice sizing and drawdown time revised per section 3 of the BMP
Manual as requested.
1 /6. Delineate wetlands on site or provide a note on plans that none exist.
V P&H Response: Note added to Sheet C1201. Also, see Page 76 of the Design
Narrative and Calculations for S&EC Preliminary Wetlands Delineation report,
,dated September 4, 2008. No wetlands exist on this site.
V/7. Plan Sheet C1201, wet pond #2, grass swale #3 is discharging into the main pond.
Please revise and redirect swale to the forebay.
1 / P&H Response: Grass Swale#3 has been removed. See Sheet C1201 for revision.
8. Revise the outlet structure detail to show a trash rack with 6" or less square
openings (Sheet C5102).
P&H Response: Trash rack with 6" square openings has been added to outlet
structure detail on Sheet C5102. See Sheet C5103 for trash rack detail.
9. On the wet pond detail show elevations for both the permanent pool and the
temporary pool (Sheet C5102).
P&H Response: Permanent and temporary pool elevations are now show on
Sheet C5102 as requested.
10. Revise all other documents to reflect above changes.
P&H Response: All documents have been revised to reflect the above revisions.
2

�11. Provide 2 sets of signed and sealed plan sheets, calculations and documents.
P&H Response: Enclosed.
Please do not hesitate to contact me if you need additional information in order to
expedite this process.
Sincerely,
49PA HILBBURN,, PPAHilburn, PLS
Principal
Enclosure
3

911 Paverstone Drive,Ste. E
P PABST& H/LBURN, PA Raleigh, NC 27615
'..I eNcraeeauwc s coNsu nrx, Office: 919.848.4399
Fax: [phone]
LETTER OF TRANSMITTAL
To: NCDENR Date: 1/21109
Division of Water Quality
943 Washington Square Mall
Washington NC 27889
Re: SECU—Swan Quarter Job No.: 102-08
Stonnwater Permit Submittal
I am sending you the following item(s):
COPIES DATE NO. DESCRIPTION
2 1/16/09 Revised Plans
2 1/19109 Revised Design Narrative and Supporting Calculations
2 1/21/09 Stormwater Permit Application (1-Original, 1-Copy)
2 Wet Pond Supplement Forms (1 -Pond#1, 1 -Pond#2)
1/15/09 - Included in Design Narrative and Supporting Calculations
2 1/21/09 O&M Agreements (1 - Pond #1, 1 - Pond#2)
Z III-Ile? ?-Vspo ssys 7-O Gpmiv�G rt S
These are transmitted as checked below:
❑ As requested ❑ For your use
® For approval ❑ For Signatures
❑ For review and comment ❑ For Submittal
Remarks:
Please find the above referenced items for approval. Do not hesitate to call if you have any
questions or need additional information. Thank you.
Copy to: File Signed:
P `. Hiibum, PLS

911 Paverstone Drive,Ste. E
&g3fB
AST& H/LBURN, PA Raleigh, NC 27615
trrv(awEI-wnc s UUNSUr_UM,' Office: 919.848.4399
Fax: [phone]
LETTER OF TRANSMITTAL
To: NCDENR Date: 10/24/08
Division of Water Quality (j(;I 1 �) ?OOf)
943 Washington Square Mall
Washington NC 27889
Re: SECU —Swan Quarter Job No.: 102-08
Stormwater Permit Submittal
I am sending you the following item(s):
COPIES DATE NO. DESCRIPTION
2 10/22/08 Plans
2 10/24/08 Design Narrative and Supporting Calculations(Includes Soil Report)
2 10/16/08 Stormwater Permit Application (1-Original, 1-Copy)
2 10/21/08 Wet Pond Supplement Forms (1 - Pond#1, 1 - Pond #2)
2 10/16/08 O&M Agreements (1 - Pond#1, 1 - Pond#2)
1 10/15/08 Permit Application Permit Fee-$505.00 (Check#23137)
These are transmitted as checked below:
❑ As requested ❑ For your use
® For approval ❑ For Signatures
❑ For review and comment ❑ For Submittal
Remarks:
Please find the above referenced items for review/approval. Do not hesitate to call if you have
any questions or need additional information. Thank you.
Copy to: File Signed
Patty E. Hilburn, PLS

. Sw►,�sAv►4XtF.0.kSF�V
STORMWATER SUBMITTAL REQUIREMENTS fl
WET DETENTION POND
I. Objective %l
A. Collect all runoff from all BUA(proposed and/or existing and/or offsite) as the case may be,
by any means including piping or swales, and direct it to the pond.
B. Check the proposed pond design to make sure it meets or exceeds the minimum design
criteria for surface area, volume and drawdown.
II. What makes up a complete wet detention pond application package?
A. Two sets of sealed, signed & dated layout & grading plans with appropriate details.
(Additional sets of plans may be requested for projects in certain counties)
B. Completed application with supplement(s), SWU-101, SW401-Wet Pond, and inspection and
maintenance agreements.
C. Deed restriction document, if applicable (for subdivisions & projects with out parcels)
D. Sealed, signed & dated calculations.
E. Estimated seasonal high water table elevation at all pond locations.
F. Chlorides test results must be provided if the project is within'/=mile of SR waters(Phase 11).
(This is only required to test out of SR water treatment requirements)
III. BIMS entry (for DWQ use only)
Enter&track application acknowledged date, review date,add info requested/received dates, permit
issue dates, and drainage area info. Best done after the add info letter is written and before sending
permit up for signature.
IV. Shell documents (for DWQ use only)
Permit shells: s:\wqs\stormwater\shells\highcompond
s:\wqskstormwater\shells\highsubpond
s:\wqs\stormwater\shells\HDhybrid
Spreadsheet: s:\wqs\stormwater\excel spreadsheets\pond
VI. Review Procedure
A. APPLICATION
✓1. An original signature is required. Photocopied signatures cannot be accepted.
✓2. A completed wet detention pond supplement and a signed, dated and notarized wet
#S�ant �t. Z detention pond Inspection and Maintenance Agreement with an original signature.
Appl. w S 3. The numbers on the supplement match up to the numbers used in the calculations and
shown on the plan details.
J4. Built-upon areas are reported in square feet in Section 111.6.
-�1 5. Receiving stream name and classification.This is important because in the non-Phase
11 counties, a wet pond cannot be used on a project that is within'/mile of and draining
to SA waters. For Phase 11, a wet pond is allowed within Y: mile of SA waters.
J6. Section 111.6 is filled in-cannot be left blank. One column must be filled in for each
proposed wet pond.
-7. If the applicant is a corporation, partnership or LLC, look it up on the Secretary of State
Corporations Database. Make sure corporationis.spelled correctly (capitalization and,
punctuation matter) and that the person sigriing the application is'at least a Vice-
president in the corporation, a General Partner in the partnership, a member in.a
member-managed LLC, or the manager of a manager-managed LLC. Need
documentation to support if the Articles.of Incorporation do not list the members or
managers of the LLC. If an agent signs,then a letter of authorization is needed from the
president, vice president, general partner, member or manager.
t+iA8. For subdivided projects, a signed and notarized deed restriction statement must be
provided.
14� '� c�eresa. ,,r��es\%MP �a w wea abet -OCN
. .vex wItK�.`h.m\ o�S�*`�
(IoJIS

Wet Detention Pond, cont.
B. CALCULATIONS
1. The orifice is sized based on drawing down the calculated minimum volume in 2-5
days. The average head to use in the orifice equation is approximately one-third of
the distance between the permanent pool elevation (PPE) and the elevation of the
next available outlet above the permanent pool. The elevation of the next available
outlet must be either the elevation where the minimum volume is provided, or it can
be higher. The temporary pool elevation (TPE) to report on the supplement will be
the elevation of the next available outlet above the PPE. The temporary pool volume
(TPV)to report on the supplement is the volume between the specified PPE and the
W4PE.
2For Phase II projects that are within '/2 mile of and draining to SR waters, the
difference in runoff from the predevelopment and post-development conditions for
3.yKthe 1 year 24 hour storm must be controlled and treated.
or Phase II projects, the discharge rate leaving the pond can be no more than the
pre-development discharge rate for the 1 year 24 hour storm.
4.0For Phase II projects draining to SA water, no discharge to surface waters may occur
from wet ponds. The discharge leaving the orifice must be effectively infiltrated prior to
reaching surface waters.
2 5. The average pond depth is the permanent pool volume divided by the permanent pool
surface area. The result must be between 3 ft. and 7.5 ft. Parts of the pond can be
eper than 7.5 ft., but in no case can any part of the pond be less than 3 ft deep.
6Y If the 85%TSS chart is used a 30' vegetated filter must be provided at the outlet of the
ond. If the 90% TSS chart is used
7. Use the co a rom the BMP Manual noting that there are different
8. ✓�c arts for different areas of the State.
equired surface area at permanent pool.
9. Provided surface area at permanent pool (Based on pond dimensions)
10. Required volume calculation based on 1.5"storm for Phase II projects*and 1"storm for
all others projects. *unless the project is Phase II and within Y mile of and draining to
/SR waters then the volume calculation must be based on difference between the pre
and post development conditions for the 1-yr 24-hr storm.
11. able of elevations, areas, incremental volumes and accumulated volumes for overall
pond and for forebay, to verify volumes provided.
12. Forebay designed to hold 20% of the permanent pool volume. (Range of 18%-22%
.)
ll i NoKn-erosive flow for 10 yr. storm in the vegetated filter, if using 85% TSS.
14. The seasonal high water table must be at or below the proposed permanent pool
/e levation to assure that the necessary volume will be available above the permanent
p ol.
15. ounding numbers off during the calculation process can result in deficiencies. Do not
round the numbers until you get to the final result.
16. An additional one foot must be excavated below the bottom elevation of the pond.The 1
foot sediment accumulation depth is not included in the average depth calculation.
deep <�r �oo}l+ �cr p> Qc�ahfy/�✓3e Sca�in�nt S�i^'���
- Av� or,n t till VSJ

Wet Detention Pond, cont.
C• PLANS- Due to stora
small S ge space constraints, plan sheets should be kept
commercial single wet pond proects, the plan set could consist of only
layout, rading and details. For larger' to a minimum. For
few eats as possible, without cl te Projects, show as 1 evelo much information as 2 or 3 sheets,
2 pment/Project Name 9 them up, possible on as gineer name and firm.
3. egend
4• North Arrow
5. Location Map with nearest intersection ytwo major roads shown. Major road is any 1,
6 �, or 3 digit NC US or interstate ale- standard engineering highway.
6: ig te
al g scale, no off-the-wall stuff.
8. vision number
g•�Zdelineating
ofivin o contours and date, if applicable.
arts, swale inveproposed contours, spot elevations, finished
10sting drainage rts, etc. floor elevations,tingg (piping• swales,ditches, ponds,etc. pipe
e the offsite drainage areas. ), including off-site. Include a map
12p rty/Project boundary lines, bearing
13. Then High Water Line or Normal High g & distances.
permanent pool elevation g Water Line, if a elevation a adjacent wetlands. Evaluate the applicable
revert dewaterin above need for AneVr andjof above lowest
�• 15, rainage Basemen wid widths,
etlands delineated, or a note on the plans that none exist. Get a co berm/slurry wall to
pipe sizes and swale inverts are provided.
delineation map signed by the Corps of Engineers, or have the applicant py of the wetlands
fthe unsigned delineation maps ubmitted to the Cor s. Wet copy
m wetlands unless a permit to fill those y include a at
16 Details for the roads, parkin wetlands has been obtained.
a
�pes. 9, cul-de-sacs, Y not be located
/1 l(i sacs, including sidewalk width, radii, dimensions&
,�// 1J partment/Condo development- Provide a
and note all concrete and wood deck areas.
18. The drainage area for each wet typical building footprint with dimensions
I
calculations eet.Yons and supplement Drainage area delineation s b stdone as a se
plan sheet. delin match up to
19 V el pond section detail to include the foreba
elevations for the bottom, pirate
above the permanent pool temporary wide vegetated shelf, pertinent
orebay, permanent pool, and the weir elevation be pool' and SH
20. The 10 ve tween the ' 3:1 slopes
� 21 9etated shelf extends 6° main pond and the
n outlet structure detail showiextends
below and 6"above the
or,
invert elevation (i.e., the a trash rack with 56"square
pool elevation.
22 elevation. permanent Pool), quire openings,the necessary
Dimensions for each line and arc formed b ) orifice size and tempora
2 ere the 85% TSS temporary spool
shown on the chart was used, a 30 the permanent pool contour.
2 mechanism). Please note that the filter strip is not a ditch tated filter strip is rebe
24. A foreba is & detailed (elevations, inverts, slopes, and w spreader
to er
25 Y provided for each inlet and located so as to flow spreader
The pond must have a minimum 1.5:1 length to width ratio and a minimum 3:1 flow
length. Artificial "baffles^ prevent short-circuiting.
path. The top elevation of the timber, vinyl, or earth can be used to create a longer flow
igher. baffle Should be set at the temporary path
26. A Vegetation plan is specified for the ry pool elevation or
listed for planting on the 101 shelf. Wee°�d, includin
271. egetated cover for pond slo p 9 Love Grassssonot suitable as a pecies are
�ll roof drainage must be directed to the Permanent
the plan. This is necessary for projects whe edthehow the roof drain collection lines on
where roof drainage may leave the site
buildings back up the property lines
prior to going through the pond.
J/gbh r�k vti erYb�i'.

• �o,.c�g co'� o�,�c��cb �o
uecn,�,
•No Foee`�rsy�pecx�'�� ' �

911 Paverstone Drive,Ste. E
P PABST& HILBURN' PA Raleigh, NC 27615
'..' ervcweer+,Ncscor✓su�nroc Office: 919.848.4399
Fax: [phone]
LETTER OF TRANSMITTAL
To: Samir Dumpor Date: 2/09/09
NCDENR - Division of Water Quality
943 Washington Square Mall
Washington, NC 27889
Re: SECU—Swan Quarter Job No.: 102-08
Stormwater Permit
I am sending you the following item(s):
COPIES DATE NO, DESCRIPTION
2 2/09/09 Revised Plan Sheet C5102 (Revised Forebay Elevation as Requested
by Samir Dumpor on 2109/09)
These are transmitted as checked below:
❑ As requested ❑ For your use
® For approval ❑ For Signatures
❑ For review and comment ❑ For Submittal
Remarks:
Please find the above referenced items for approval. Do not hesitate to call if you have any
questions or need additional information. Thank you.
Copy to: File Signed CS44
Pa . Hilburn, PLS

911 Paverstone Drive,Ste. E
PABST& H/LBURN, PA Raleigh, NC 27615
PH ENGINEERING 8 CONSULTING FEB 1 9 2009 Office: 919.848.4399
Fax: [phone]
LETTER OF TRANSMITTAL
To: Samir Dumpor Date: 2/18/09
NCDENR - Division of Water Quality
943 Washington Square Mall
Washington NC 27889
Re: SECU—Swan Quarter Job No.: 102-08
Stonnwater Permit
I am sending you the following item(s):
COPIES DATE NO. DESCRIPTION
2 2/18/09 Revised Plan Sheet L1301 (Revised Vegetated Shelf Plantings)
These are transmitted as checked below:
❑ As requested ❑ For your use
® For approval ❑ For Signatures
❑ For review and comment ❑ For Submittal
Remarks:
Please find the above referenced items for approval. Do not hesitate to call if you have any
questions or need additional information. Thank you.
Copy to: File Signed: �,
latty . Hilburn, PLS

r
DESIGN NARRATIVE AND
SUPPORTING CALCULATIONS
FOR
STORMWATER RMP'S, STORM DRAINAGE,
AND EROSION AND SEDIMENT CONTROL
FOR THE
( JAN 2 3 2009
( State Employees' Credit Union
( US Hwy 264
( SWarl Quarter, Hyde County, north Carolina,
Prepared for:
( State Employees' credit Union
( c/o O'Brien Atkins Architects
( PC) BOX 12037
RTP, NC 27709
( [phone]
l
Preparers by:
mmn
� ® PtiBSf& Fild_AURN, Pf:
l H1
l 911 Paverstone Drive, Suite E SEAL
9``t
Raleigh, NC 27615 032573 '
[phone] %
Date: January 19, 2009
l Project No.: 102-08
l
t.
L-

r
TABLE OF CONTENTS
Pape
Design Narrative 1 -3
USGS Map 4
Hyde County Soil Survey 5
FEMA Flood Map 6
Division of Water Quality Permitting Information 7
NOAA —Swan Quarter Precipitation Intensity Estimates 8
NOAA —Swan Quarter Precipitation Frequency Estimates 9
Wet Pond #1 Design
• Wet Detention Basin Supplement 10— 12
• Water Quality Calculations 13 —20
• Time of Concentration — Pre-Development 21
• Pre-Development Hydrograph (1-yr, 24 hr Storm) 22
• Post-Development Hydrograph (1-yr, 24 hr Storm) 23
• Pond Design Report 24
• Pond Routing Hydrograph ((1-yr, 24 hr Storm) 25
• Riser Structure Buoyancy Calculation 26
Wet Pond #2 Design
• Wet Detention Basin Supplement 27 —29
• Water Quality Calculations 30 - 37
• Time of Concentration—Pre-Development 38
• Pre-Development Hydrograph (1-yr, 24 hr Storm) 39
• Post-Development Hydrograph (1-yr, 24 hr Storm) 40
• Pond Design Report 41
• Pond Routing Hydrograph ((I-yr, 24 hr Storm) 42
• Riser Structure Buoyancy Calculation 43
Hydrograph Summary for Pond #1 and Pond #2
• 1-year, 24 hour Storm 44
• 10-year, 24 hour Storm 45
• 100-year, 24 hour Storm 46

I
SCS Curve Number Calculations 47
Storm Drainage Design (10-yr Storm) 48— 53
Hydraulic Grade Line (10-yr Storm) 54
i
Outlet Protection Design 55 - 58
Sediment Trap Design
Trap #1 59
Trap #2 60
Grass Swale Design
Grass Swale#1 61 - 63
Grass Swale#2 64 - 66
Culvert Design 67 - 70
Permanent Seed Specifications 71
Soil Evaluation Report by S&EC 72 - 75
Preliminary Wetland Delineation Report by S&EC 76 - 77
Drainage Area Maps
• Pre-Development Drainage Area Map Sheet 1
• Post-Development Drainage Area Map Sheet 2
• Storm Drainage Area Map Sheet 3

r
I
DESIGN NARRATIVE
1. GENERAL
The project site is located along US Hwy 264 and is approximately 0.40 miles west of the
intersection of US Hwy 264 and SR 1166 in Swan Quarter, N.C. The intent of this project is to
construct a new building, parking, utilities, and storm drainage features required to serve the
project.
2. EXISTING SITE
The existing site is located in the coastal area and is within 1/2 miles of SA waters. The site was
utilized for many years as farm land and is currently undeveloped. Topographically, the site is
mostly flat (approximately 0.50%). Currently, the runoff from this site is collected in farm
ditches near the eastern and northern property lines and located on the adjacent properties. A
series of ditches direct the runoff to Swan Quarter Bay.
Based on Hyde County Soil Survey, the existing soils are RoA (Roper muck) and HyA
(Hydeland silt loam). The FEMA Flood Insurance Rate Map shows the project site to be located
in Zone AE with a 100-year flood elevation of approximately 6.5 to 7.0. The USGS map, the
Hyde County soil survey map, and the FEMA map are included in this report.
3. PROPOSED IMPROVEMENTS
This project will have a disturbed area of 2.40 acres, in which the majority of the disturbed area
will be utilized for the construction of the building, parking areas, storm drainage, stormwater
BMP's, sidewalks and vegetated slopes.
The majority of stormwater runoff from the proposed improvements will be initially directed by
sheet flow into curb inlets located in the parking area. The storm drainage system will carry the
runoff to wet detention ponds, as shown on plans. The storm drainage system was designed
for the 10-year storm with a minimum slope of 0.50%. A complete set of calculations, including
hydraulic grade line calculations, for the stormwater drainage are attached.
Stormwater Control and Treatment
The current NCDENR Coastal Stormwater Rules require the control and treatment of runoff
generated by 1.5" of rainfall OR the difference in runoff from the pre and post development
conditions for the 1-year, 24-hour storm (whichever is greater) for a site that is located within '/2
mile of SA waters. The runoff volume for 1.5" of rainfall was calculated to be 1,443.6 cubic feet
for drainage area #1 and 2,882.3 cubic feet for drainage area #2. The difference between the
pre and post development conditions for the 1-year, 24-hour storm runoff volume was
calculated to be 1,640 cubic feet for drainage area #1 and 3,724 cubic feet for drainage area
#2. This site is required to satisfy water quantity one as a result of the runoff volume for the 1-
year, 24-hour storm being greater than the runoff volume from the 1.5" rainfall for both drainage
areas. However, water quality was also considered when designing the BMP devices.
A soil evaluation prepared by Soil & Environmental Consultants (S&EC) dated September 4'",
2008, states that the infiltration rate of the existing soils is well below 0.52 inches/hour. The
evaluation further states that the soil morphology (munsell color) from the 4 borings indicate the
l

i
seasonable high water table to be less than 12 inches deep. Based on the above information,
the soil conditions are not favorable for a stormwater infiltration device. A copy of the soil
evaluation prepared by S&EC is attached.
Water Quantity
Using SCS (TR-55) Method, the ponds were designed to release the post-development 1-yr,
24-hr storm at a rate less than or equal to the pre-development 1-yr, 24-hr storm as required by
NCDENR. See table below for results of pre-post development calculations.
Wet Pond #1 1- ear, 24-hour Storm
Pre-development Post-development Pond
Total Drainage Area Runoff Runoff Discharge after
(cfs) (cfs) Routing (cfs)
0.47 Ac. 0.36 1.81 0.04
Wet Pond #2 1- ear, 24-hour Storm
Pre-development Post-development Pond
Total Drainage Area Runoff Runoff Discharge after
(cfs) (cfs) Routing (cfs)
0.90 Ac. 0.68 3.71 0.56
A complete set of calculations have been included in this report.
Water Quality
The wet detention ponds were also designed for 90% TSS removal for the first 1.5" of runoff
given that the storm water from the ponds will discharged into and existing roadside ditch and
not into a vegetated filter strip. The volume of runoff generated from the 1.5" rainfall will be
drawn down at a rate between 2 to 5 days. Copies of the water quality calculations have been
included in this report.
CAMA
Steve Trowell, with the Division of Coastal Management, was contacted concerning whether or
not a CAMA permit for the subject site was required. Mr. Trowell stated that the site is not
included in an area of the Division's jurisdiction and therefore, is not subject to CAMA
permitting.
4. EROSION CONTROL AND MAINTENANCE CONSIDERATIONS
Temporary silt fence will be placed along the lowest sides of the limits of disturbance to cleanse
stormwater runoff before leaving the site. Temporary diversion ditches will be installed to direct
stormwater runoff from the site to sediment traps. Inlet protection will be placed around all new
drainage structures that may be affected by the proposed construction. Calculations for the
design of the sediment trap are attached. All erosion control measures are documented on the
enclosed erosion control plan.
Contractors shall be responsible for periodic inspection and maintenance of all indicated
erosion control devices. In addition, inspection and any necessary maintenance will be required
v

immediately following any significant storm event. Any measure that fails to function as
intended shall be repaired immediately. Upon completion of construction, the property owner
shall be responsible for site maintenance.
�1

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Project No. FI ure 2 - USGS 1 :24k
11141 .52 9
Topocyaghlc Quadrangle
Project Mcjr.:
,SIC Swan Quarter SECU Soil & Environmental Consultants, PA
hyde County, NC 11010 Raven Ridge Rd.- Raleigh,INC 27614
5cale: [phone]•[phone]
I" = 2,000'
Web Page: www-SandEC.com
05/20/08 1 5wanquarter Quadrangle

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Project No. Figure 2 - NKCS I :24k
11141.52
County Sod Survey
Project Mgr.:
WC Swan Quarter SECU Soil & Environmental Consultants, PA
Hyde County, NC 11010 Raven Ridge Rd.- Raleigh,NC 27614
5cale: [phone]•[phone]
I" = 2,000'
Web Page: www.SandEC.corn
08/20/05 Sheet 39
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North Carolina Areas Subject to Phase 11 Post-Construction & Other Stormwater Program... Page 1 of 1
i
( N.C. Division o Water Quality about the oimsion i contact us I dwq sections(glossary
C.�.\ ._.'To preserve,pmtect
1.JIlK.�I and enhance
North Carolina's wales
Address Lat/Long Results
t Permitting : State
® � .� ✓syt`; ��Yt�+.w'y,.ras3a s r, }u tr ��„�3i.
Type: SA-Shellfish Waters
Basis: HQWORW .__;.
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Category: SA waters fl
Notes: �N 264 '
State Stormwater n
Contact: Permitting DWQ 19
Regional
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County: HYDE
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DENR Region: Washington tn�
htip://204.211.239.202/stormwateT/ g/l/200g

rreclpltation rrequency Vata Server Page 1 of 3
5EeA,4 - SW4t-) Cam.M-T -
( POINT PRECIPITATION �jam_
1EN FREQUENCY ESTIMATES
l FROM NOAA ATLAS 14
North Carolina 35.42 N 76.36 W 0 feet
hom"Preclptlation-Frequency Alias of the United Sta1C"NOAA Allis 14,Volume 2.Vasiun i
G.M.Nnnnln,n.Martin.❑.I.in.'I'.Panyhuk,M.yekn.and D.Riley
f NOAA.National Weather Smic,Silver Spring,Maryland,21HW
P:vtraelcd:1'ri Aug 1 2008
Confidence Limits Seasonality Location Maps Other Info. GIs data Maps Help D� Map-
Precipitation Intensity Estimates (in/hr)
(AyeRa1r*s)Fmq m 1m 12 24 48 10 20 1 45 60
terd
h m 3 hr 6 r hrte dfp dy dfn min h 1�5.64 4.50 3.75 2.57 1.60 0.95 0.68 0.41 0.24 0.14 0.08 O.OS 0.03 0.02 0.02 0.01 0.01 0.01
2�6.42 5.14 4.30 2.97 1.86 1.1 1 0.80 0.48 0.28 0.17 0.10 0.06 0.04 003. 0.02 0.02 0.01 0.01
7.06 5.65 4.76 3.39 2.17 1.32 0.95 0.57 0.34 0.23 0.13 0.07 0.05 0041 0.02 0.02 0.02 0.01
lF 10 8.27 6.61 5.58 4.04 2.63 1.63 1.1E 0.72 0.42 0.27 0.15 0.08 0.06 0.04 0.03 0.02 0.02 0.02
I 25 9.29 7.40 6.26 4.63 3.08 1.95 1.43 0.87 0.52 0.33 0.19 0.10 0.07 0.05 0.03 0.03 0.02 0.02
50 10.34 8.23 6.95 5.23 3..5.5 2.29 1.70 1.03 0.62 0.39 0.22 0.12 0.08 0.06 0.04 0.03 0.02 0.02
100 11.21 8.90 7.50 5.75 3.96 2.60 1.95 1.19 0.72 0.45 0.26 0.14 0.09 0.06 0.04 0.03 0.03 0.02
200 12.07 9.56 8.04 6.26 4.39 2.94 2.23 1.37 0.83 0.51 0.30 0.15 0.10 0.07 0.05 . 0.03 0.03 0.02
500 I 13.02 10.30 8.64 6.88 4.93 3.37 2.59 1.60 0.98 0.61 0.36 0.18 0.11 0.08 0.05 0.04 0.03 0.03
]000 14.09 11.09 9.28 7.51 5.49 3.82 2.98 1.84 1.14 0.69 0.41 0.21 0.13 0.09 0.06 0.04 0.04 0.03
i
These pieciplation frayaency estimates are based on a camel duration series ARI is the Average aecucence Interval.
Please refer to the documonfaW.for more information.NOTE formatting forces estimates near zero to appear as zero.
* Upper bound of the 90% confidence interval
Precipitation Intensity Estimates(in/hr)
ARI** 5 ]0 15 30 60 120 3 6 12 24 48 4 7 ]0 20 30 45 60
(years) min min min min min min hr ter ter hr ter day day day day day day day
1�6.22 4.96 4.14 2.84 1.77 1.0E 0.77 0.47 0.27 0.16 0.09 0.05 0.03 0.03 0.02 0.01 0.01 0.01
07.06 5.65 4,73 3.27 2.05 1.23 0.89 0.55 0.32 0.19 0.11 0.06 0.04 FO 0-31 0.02 0.02 0.01 0. 11
=7.75 6.21 5.2 3.72 2.38 ].46 1.06 0.65 0.38 0.25 0.14 0.08 0.05 0.04 0.03 0.02 0.02 0.02
! to 9.07 7.25 6.12 4.43 2.89 1.80 1.32 0.E1 0.48 0.30 0.17 0.09 0.06 0.05 0.03 0.02 0.02 0.02
25 10.19 8.12 6.86 5.08 3.38 2.15 1S9 0.9E 0.58 0.37 0.21 0.11 0.07 0.06 0.03 0.03 0.02 0.02
50 11.33 9.02 7.61 5.73 3.88 2.52 ].88 1.16 0.69 0.43 0.24 0.13 0.08 0.06 0.04 0.03 0.03 0.02
500 12.29 9.76 8.22 6.30 4.34 2.86 2.16 1.33 0.80 0.49 0.28 0.15 0.09 0.07 0.04 0.03 0.03 0.02
200 13.21 10.48 8.81 6.86 4.81 3.23 2.47 1.53 0.92 0.56 0.33 0.17 0.11 0.08 0.05 0 04TO-031 0.03
500 14.29 11.30 9.48 7.55 .5.41 3.71 2.88 1.78 1.09 0.67 0.40 0.20 0.12 0.09 0.06 0.04 0.04 0.03
1000 15.48 12.19 10.20 8.26 6.03 4.21 3.31 2.06 ].27 0.77 0.46 0.23 0.14 0.10 0.06 0.05 0.04 0.03
'The upper tsum)of the confidence interval at 90%confidence level is the value which S%of the simulated quintile values for a given Irequency are greater Nan.
^These preciptation mequency estimates are teased on a oriel duration ser'es ARI is the Average Recurrence Interval.
Please refer to the AocumWat or for more information.NOTE:Pormaang prevents estimates near zero to appear as m.
* Lower bound of the 90% confidence interval
Precipitation Intensity Estimates(in/hr)
ARI 5 10 15 30 60 120 3 6 12 24 48 4 7 ]0 20 30 45 60
(years) min min mm mm mm min hr ter ter ter ter da da da dety 11 day da da
05.12 4.09 3.4] 2.34 1.46 0.85 0.61 0.37 0.22 0.13 0.08 0.04 0.03 1 0.02 0.02 0.01 0.01 O.OI
5.88 4.70 3.9 4 2.72 1.71 1.01 0.72 0.44 0.25 0.16 0.09 0.05 0.03 0.0 30.02 0.02 0.01 0.01
OS 6.46 5.17 4.36 3.10 1.98 1.19 0.86 0.52 0.30 0.21 0.12 0.07 0.04 0.03 0.02 0.02 0.01 0.01
10 7.54 6.03 5.08 3.68 2.40 1.47 1.06 0.64 0.38 0.24 0.14 0.08 0.05 FO 0-41 0.03 0.02 0.02 OAI
25 8.42 6.71 5.67 4.20 2.80 1.75 1.28 0.77 0.46 0.30 0.17 0.09 0.06 0.05 0.03 0.02 0.02 0.02
50 9.34 7.43 6.28 4.73 3.20 2.05 1.51 0.91 0.54 0.34 0.20 0.11 0.07 0.05 0.03 0.03 0.02 0.02
100 1 10.08 8.01 6.75 5.17 3.56 2.32 1.72 1.05 0.63 0.39 0.23 0.12 0.08 006 FO 0-41 0.03 0.02 0.02
U
http://hdsc.nws.noaa.gov/cgi-bi n/hdsc/bu i l dout.perl?type=idf&units=u s&se ries=pd&state n a... 8/1/2008

Precipitation Frequency Data Server Page 1 of 4
r
( POINT PRECIPITATION a`
FREQUENCY ESTIMATES
( FROM NOAA ATLAS 14
1 North Carolina 35.42 N 76.36 W 0 feel
form"Precipilalum Frequency Atlas of the Uniled States NOAA Atlas 14.Volume 2.Version 1
G.M.nnnnin,Il.Martin,❑.Lin, I,Pa nybok.M.Vekta,and D.Riley
t NOAA,National Weather Service,Silver Spring.Maryland,2004
Ealm,wd,Pri Aug 1 20T8
i Confidence Limits Seasonality L Location Maps .Other Info. GIS data Maps Help i D�cs i U.S.Map_j
I Precipitation Frequency Estimates (inches)
AR7 S 10 Ic 311 hll LO 111 0 311 45 MI
* 1 hr G hr 12 hr 241v 48 hr 4 day 7 d:p' ❑❑ ❑
(years) min min min min min m_in day day dal d:n day
1�0.47 0.75 0.94 1.29 1.60 1.9 0 2.05 2.47 3.97 4.49 5.22 5.91 Et9.83 12.15 14.56
i 00.54 0.86 1.08 1.49 1.8G 2.23 2.40 2.89 3.40 4.18 4.82 5.43 6.30 7.08 9.48 11.69 14_i8 17.18
�0.59 0.94 1.19 1.69 2.17 2.63 2.85 3.44 4.06 5A1 6.18 6.91 291 8.77 1L52 14.OG I -- 20.30
10 0.69 1.10 1.39 2.02 2.63 3.26 3.55 4.28 5.08 6.44 7.36 8.13 9.25 10.16 13.20 15.96 19.52 22.80
f 25 0.77 1.23 1.56 2.32 3.08 3.90 4.30 5.20 6.21 7.96 9.13 9.91 11.16 12.17 15.57 18.58 22.78 26.21
( 50 0.86 1.37 1.74 2.62 3.55 4.58 5.09 6.19 7.44 9.27 10.66 11.40 F12 761 13.83 17.52 20.67 fl 28.91
( 100 0.93 1.48 1.88 2.87 3.96 5.21 5.86 7.14 8.65 10.70 12.37 13.04 14.47 15.59 19.57 22.81 28.18 31.65
200 1.01 1S9 2.01 3.13 4.39 5.88 6.69 8.18 9.98 12.28 14.28 14.82 16.30 17.48 21.72 25.01 31.06 34.43
500 1.08 1.72 2.16 3.44 4.93 6.75 7.79 9.57 1i.76 14.63 ]7.15 1247 18.95 20.17 24.7.5 28.01 35.08 38.19
i ]000 1.17 1.85 2.32 3.76 5.49 7.64 8.95 11.04 13.69 16.63 19.G3 19.87 21.18 22.39 27.19 30.37 38.28 41.09
These precipitation frequency estimates are based on a partial duration series ARI is the Average Recurrence Interval.
i Please refer to the docurnareabm for more informal NOTE'Formall forces estimates near zero to appear as zero.
* Upper bound of the 90% confidence interval
Precipitation Frequency Estimates (inches)
j ARI•• ❑5 ]0 15 30 60 120 ❑3 6❑ 12 24 48 ❑4 7❑ 10 20 30 45 6U
�(years)� mm mm mm mm mm mm hr hr hr hr hr day day day 11 day 11 day 11 day day
I 10.52 0.83 1.03 1.42 1.77 2.11 2.31 2.81 3.30 3.81 4.41 4.93 5.70 6.41 8.57 10.52 13.01 15.50
0 0.59 0.94 1.18 1.63 2.05 2.46 2.68 3.26 3.84 4.64 5.35 5.97 6.88 7.70 10.21 12.51 15.40 18.30
��0.65 1.03 1.31 1.86 2.38 2.92 3.19 3.88 4.58 5. 99 6.86 7.60 8.64 9.54 12.42 15.05 18.40 21.62
10 0.76 1.21 1.53 2.22 2.89 3.59 3.96 4.83 5.73 7.11 8.15 8.94 10.08 11.05 14.21 17.07 20.86 24.28
25 0.85 1.35 1.72 2.54 3.38 4.30 4.78 5.85 6.98 8.78 ]0.07 10.89 12.16 13.22 16.77 19.86 24.36 27.95
50 0.94 1.50 1.90 2.87 3.88 FT5.66 FT8.33 10.21 11.7 ]5 12.54 3.90 15.03 18.87 22.10 27.22 30.85
]00 1.02 1.63 2.06 3.15 4.34 5.73 6.50 7.99 9.67 1L77 13.66 14.36 ]5.79 16.97 21.11 24.41 30.21 33.82
200 1.10 1.75 2.20 3.43 4.81 6.46 7.41 9.14 11.14 13,53 1.5.79 16.34 17.82 19.06 23.49 26.85 33.41 36.88
500 1.19 1.88 2.37 3.77 .5.41 7.43 8.64 10.68 13.13 16.17 19.05 19.35 20.80 22.13 26.91 30.20 37.90 41.08
1000 1.29 2.03 2.55 4.13 6.03 8.42 9.94 12.33 15.28 18.43 21.90 22.14 23.40 24.69 29.71 32.88 41.55 44.40
•The upper bound of the confidence interval at 90%confidence level's the value which 5%of Me simulated quartile values lot a given frequency are greater than
••These precipitation frequency estimates are based on a partial duration series ARI is Me Average Recurrence Interval.
Please refer to Mar documenapcn for more information.NOTE:Formatting prevents estimates near zero to appear as zero.
* Lower bound of the 90%p confidence interval
Precipitation Frequency Estimates (inches)
6 20 AR • 15 30 0 3r6❑ ]2 24 48 ❑4 7 0 20 30 5 604
ayay15 mmmmm hh hr In hr d ❑ddy day day day dayyea ❑m r-]0.43 0.68 0.85 1.17 1.46 1.71 1.84 2.21 2.60 3.14 3.62 4.12 4.82 5.47 7.42 9.19 11.41 13.70
2 0.49 0.78 0.98 1.36 ].7] 2.02 2.17 2.60 3.06 3.82 4.39 4.98 SEI 6.56 8.85 10.93 13.50 16.17
0 0.54 O.Rb 1.09 1.55 1.98 2.39 2.57 3.09 3.65 4.93 5.62 6.33 7.28 8.11 10.74 13.13 16.12 19.10
]0 0.63 I.00 1.27 1.84 2.40 2.94 3.19 3.84 4.55 5.84 6.66 7.42 8.47 9.37 12.29 14.87 ]8.24 21.41
25 0.70 1.12 1.42 2.10 2.80 3.51 3.84 4.64 5.53 216 8.20 8.98 10.16 11.15 14.41 17.23 21.19 24.53
50 0.78 1.24 1.57 2.36 3.20 4.- 4.52 5.48 G.SG 8.28 9.49 10.25 11.54 12.58 16.12 19.07 23.54 26.96
100 0.84 1.33 1.69 2.58 3.56 4.64 5.17 6.28 7.56 9.47 10.90 11.62 12.971 14.07 17.87 20.93 E9fl 29.36
http://hdsc.nws.noaa.gov/cgi-bin/hdsc/bu i l dout.perl?type=pf&units=us&series=pd&statena... 8/1/2008

1 Pe,rnd N.
(to be provOed by OWO)
1
•Y A W OF A 7EF
( NCDENR r
( STORMWATER MANAGEMENT PERMIT APPLICATION FORM o T
{ 401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled oul,printed and submitted.
The Required Items Checklist(Part I//)must be printed,filled out and submitted along with all of the required information.
( I. PROJECT INFORMATION
Project name State Employees Credit Union-Swan Quarter
( Contact person Patty E.Hilburn
( Phone number (919)8484399
Dale 111512009
( Drainage area number Pond#1
( II. DESIGN INFORMATION
Site Characteristics
Drainage area. 20,467 ft'
( Impervious area,post-development 11,695 ft3 ✓
%impervious 57.14% /
( Design rainfall depth ..5 in V
( Storage Volume: Nori Waters
Minimum volume required ft3
Volume provided ft3
Storage Volume: SA Water
( 1.5'runoff volume 1,448 ft3 .V/
1 Pre-development 1-yr,24-hr runoff 207 ft3 #REFI
Post-development 1-yr,24-hr runoff 517 ft3 / #REFI
( Minimum volume required 1,448 rya' -Y//
( Volume provided 2901 ft3
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required? y (Y or N)
( 1-yr,24-hr rainfall depth 3.4 in
1 Rational C,pre-development 0.25(unitless)
Rational C,post-development 0.65(unidess)
t Rainfall intensity:1-yr,24-hr storm 5.64 in/hr OK
Pre-development 1-yr,24-hr peak flow 0.43 ft3/sec
Post-development 1-yr,24-hr peak flow 1.89 ft3/sec
I Pre/Post 1-yr,24-hr peak flow control 1.46 ft3/sec
Elevations
Temporary pool elevation 2.75 fmsl
t Permanent pool elevation 2.00 fmsl
SHWT elevation(approx.at the perm.pool elevation) 1.40 fmsl
Top of 10ft vegetated shelf elevation 2.50 knell
Bottom of 10ft vegetated shelf elevation 1.50 fmsl
l Sediment cleanout,lop elevation(bottom of pond) -3.00 fmsl
Sediment cleanoul,bottom elevation .4 00 fmsl
Sediment storage provided 1.00 ft V
I Is there additional volume stored above the state-required temp.pool? n (Y or N)
f Elevation of the lop of the additional volume 2.8 fmsl OK
l
l
Form SW401-Wet Detention basin-Hev.5 Parts L 811.Design Summary,Page 1 of 2
l kv

( Permit No.
- nn be provided by DWO7
II. DESIGN INFORMATION
Surface Areas
Area,temporary pool 4,705 tt' -V`'
Area REQUIRED,permanent pool 1.378 ft'
SAIDA ratio 6.50(unitless) V
Area PROVIDED,permanent pool,Ap,,,, _ 2,443 fl' OK
Area,bottom of 10ft vegetated shelf,P.d,d, 1,500 ft,
( Area,sediment cleanout,top elevation(bottom of pond),A,y,.,a 294 ft'
( Volumes
( Volume,temporary pod 2,901 RI / OK
Volume,permanent pool,V,,n_P, 4.985 ft" y
Volume,forebay(sum of forebays if more than one forebay) 996 ft,
Forebay%of permanent pool volume 20.0%% OK
( SAIDA Table Data V
Design TSS removal 90%
Coastal SAIDA Table Used? y (Y or N)
( Mountain/Piedmont SAIDA Table Used? n (Y or N)
SAIDA ratio 6.50 limitless)
Average depth(used in SAIDA table):
( Calculation option 1 used?(See Figure 10-2b) It (Y or N)
Volume,permanent pool,Vp„,-. It,
( Area provided,permanent pool,Ar,,,,� fle
Average depth calculated It
Average depth used in SAIDA,d„,(Round to nearest 0.5ft) It
( Calculation option 2 used?(See Figure 10.2b) y (Y or N)
I
Area provided,permanent pool,Ap,,,.. 2.443 ft' OK
Area,bottom of 1 Oft vegetated shelf,Ab�.,,,y, 1,500 ft OK
( Area,sediment cleanout,lop elevation(bottom of pond),A.., 294 ft' OK
( 'Depth'(distance b/w bottom of IN shelf and top of sediment) 4.50 It OK
Average depth calculated 3.06 ft OK
Average depth used in SAIDA,d„,(Round to nearest 0.5ft) 3.1 it OK
Dfawdown Calculations
( Drawdown through orifice? If (Y or N) j
Diameter of orifice(if circular) 0.75 in
( Area of orifice(if-noncimulaQ ins
Coefficient of discharge(Co) 0.60(uniless)
( Driving head(H,) 0.75 8
( Drawdown through weir.) - n (Y or N)
Weir type (unilless)
( Coefficient of discharge(C„) (unilless)
t Length of weir(L) It
Driving head(H) ft
Pre-development 1-yr,24-hr peak flow 0.70 ft`/sec OK
Post-development 1-yr,24-hr peak flow 1.72 fOlsec OK
i
Storage volume discharge rate(through discharge orifice or weir) 0_01 tt'/sec %
Storage volume drawdown time 2.62 days
J OK,draws down in 2-5 days.
OK,drawdown time is coned.
Additional Information
Vegetated side slopes 3:1 OK
Vegetated shelf slope 10:1 OK
Vegetated shelf width 10.0 N OK
Length of flowpath to width ratio _ 3:1 OK
Length to width ratio 2.6:1 OK
Trash rack for overflow 8 onfice? y (Y or N) OK
Freeboard provided 1.3 It QK
Vegetated filter provided? n (Y or N) /nu
1 Recorded drainage easement provided? _ n (Y or N) nlcT ?k Z7-1 c Cb PiElz- faM/Pe-uTaN c.l( 5A A 12- D ,
Capures all runoff at ultimate build-out? y (Y or N) OK
t Drain mechanism for maintenance or emergencies Ports to be pumped for emergency or maintenance purposes
Form SW401-Wet Detention Basin-Rev.5 Parts I.a II.Design Summary,Page 2 of 2

I
Permit No.
(to be provided by DWO)
r 111. REQUIRED ITEMS CHECKLIST
t
i Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent,the agent may initial below. If a
requirement has not been met,attach justification.
' Pagel Plan
gals Sheet No.
CI Zl6 1 1. Plans(1"-50'or larger)of the entire site showing:
-Design at ultimate build-out,
-Off-site drainage(if applicable), n/)A
gviGIIIW�14 Z,Delineated drainage basins(include Rational C coefficient per basin), — 5c5. ME771e0 LAS&O
Cstpy -Basin dimensions, — 0"1,4144 5 ln6clw,16n I^.)
-Pretreatment system, Pea aA+24 A4A_.9-nje, 4.
! -High flow bypass system, ,b
i
-Maintenance access,
-Proposed drainage easement and public right of way(ROW),
-Overflow device,and
-Boundaries of drainage easement.
I CSlo2 2. Parlial plan(1"=30'or larger)and details for the wet detention basin showing:
-Outlet structure with trash rack or similar,
-Maintenance access,
-Permanent pool dimensions,
i -Forebay and main pond with hardened emergency spillway,
-Basin cross-section,
I -Vegetation specification for planting shelf,and
I -Filter strip. �JI.4 — ')4,-/. T55 RZn'Ov'4L-
i Ala Z 3. Section view of the wet detention basin(1"=20'or larger)showing:
-Side slopes,3:1 or lower,
-Pretreatment and treatment areas,and
-Inlet and outlet structures.
s�� ( 12y! 4. If the basin is used for sediment and erosion control during construction,clean out of the basin is specified
on the plans prior to use as a wet detention basin.
PP9.6 -11 5. A table of elevations,areas,incremental volumes&accumulated volumes for overall pond and for forebay,
to verify volume provided.
J?f,&t't C 1201 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
PE)i w 7. The supporting calculations.
4-1
P_g� e\.� 8. A copy of the signed and notarized operation and maintenance(0&M)agreement.
rIW 9. A copy of the deed restrictions(if required).
72--7')10. A soils report that is based upon an actual field investigation,soil borings,and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.5 Pan III.Required Items Checklist,Page 1 of 1
V

i
WATER QUALITY POND #1
CALCULATIONS
Project Name
SECU - Swan Quarter
Project Number
102-08
Date
13-Jan-09
3rd revision _
2nd revision
1 st revision
l�

r
i
r Water Quality Pond Drainage Area Data
r
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 1
Date 13-Jan-09
Total site area 20,467 square feet = 0.47 acres
Drainage area to and Other Drainage Area
TO
Proposed Change Existing Proposed
Impervious areas s s s s
On-site buildings 0 0 0 0
On-site streets 0 0 0 0
On-site parking10,421 10,421 0 0
On-site sidewalks 1,199 1,199 0 0
Other on-site 75 75 0 0
Total off-site impervious 0 0 0 0 0
Total Impervious 0 11,695 11,695 0 0
Drainage area to and Other Drainage Area
Existing Proposed Change Existing Proposed
Non-impervious areas lsfl Isf] s s s
On-site grass/landscape 0 8,772 8,772 0 0
On-site woods 0 0 0 0 0
Other undeveloped 20,467 0 -20,467 0 0
Total off-site non-impervious 0 0 0 0 0
Total non-impervious 20,467 8,772 71,695 0 0
Total Drainage Area 20,467 1 20,467 0 0 0
Percent Impervious 0.0 1 57.1 57.1 n/a n/a
Notes:
Water Quality Pond 1 Calculations
Site Drainage Area Data Page 1 of 1 Printed 1/15/2009 4:31 PM

l
Water Quality Pond Surface Area Calculations
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 1
Date 13-Jan-09
I"
( Total on-site drainage area to pond 20,467 square feet
Total impervious area in drainage area 11,695 V square feet
Average water depth of basin at normal pool 3.06 feet r
r
( Location of site Swan Quarter
Site region Coastal
% Impervious cover 57.1 percent
( If the site is in a coastal area, will a vegetative filter be used? No
( Surface Area/Drainage Area Ratios:
l For a site in the Piedmont 2.28 percent
For a site in a Coastal County w/Vegetative Filter 4.70 ercent
For a site in a Coastal County w/out Vegetative Filter 6.50 percent
( Required surface area of pond:
I For a site in the Piedmont 470.0 square feet
For a site in a Coastal County w/Vegetative Filter 970.0 square feet
1 For a site in a Coastal County w/out Vegetative Filter 1,340.0 square feet
l
I Notes:
i
Water Quality Pond 1 Calculations
Pond Surface Area Calcs Page 1 of 1 Printed 1/15/2009 4:31 PM
j$

Water Quality Pond Stormwater Runoff Volume Calculations
r
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 1
Date 13-Jan-09
` Drainage area 20,467 square feet
Impervious area 11,695 square feet
Rainfall depth 1.50 inches
` Percent Impervious 57.1 percent
R(v)=0.05+0.009*(Percent impervious)
Runoff coefficient - R(v) 0.56 in/in
i
Runoff volume=(Design rainfall)*(R(v))*(Drainage area)'
Runoff volume 1,443.6 cubic feet ,VI
Notes:
i
Water Quality Pond 1 Calculations
Runoff Volume Calcs Page 1 of 1 Printed 1/15/2009 4:31 PM
�U

i
POND STAGE-STORAGE DATA
PERMANENT POOL
Project SEC -Swan Quarter
Project No. 102-08
Pond No 1
Date 13-Jan-09
Incremental Incremental Incremental Incremental Cumulative Cumulative
Contour ID Stage Area Area Area Area volume volume volume volume
s . tt. acres [sq.ft.l Jacres cu.ft acre-ft cu. tt acre-tt
-3 0 294.1 0.007 294.1 0.0 0.0 0.0 0.0 0.0
-2 1 506.1 0.012 212.0 0.0 400.1 0.0 400.1 0.0
-1 2 750.1 0.017 244.0 0.0 628.1 0.0 1,028.2 0.0
0 3 1,026.1 0.024 276.0 0.0 888.1 0.0 1,916.3 0.0
1 4 1,334.1 0.031 308.0 0.0 1,180.1 0.0 3,096.4 0.0
2 5 2,442.5„ 0.056 1,108.4 0.0 1,888.3 0.0 4,984.7 0.1
i
Forebay Volume: 20%of Volume=approx. 997 cu.tt
-1 0 115.0 0.003 115.0 0.0 0.0 0.0 0.0 0.0
0 3 243.0 0.006 128.0 0.0 179.0 0.0 179.0 0.0
1 4 402.1 0.009 159.1 0.0 322.6 0.0 501.6 0.0
f 2 5 587.2 0.013 185.1 0.0 494.7 0.0 ',9$B,a_,:, 0.0
i
i
Water Quality Pond 1 Calculations
Stage-Storage(Perm Pool) Page 1 of 1 Printed 1/15/2009 3:56 PM

1/
1/
I
j POND STAGE-STORAGE DATA
VOLUME REQUIRED
f Project SECU -Swan Quarter
Project No. 102-08
I Pond No. 1
Date 13-Jan-09
Incremental Incremental IncrementalFlncremental Cumulative Cumulative
Contour ID Stage Area Area Area Area volumeme volume volume
[sq.ft. acres s .ft. acres cu.ft -tt cu. tt acre-ft2 0 3,029.7 0.070 3,029.7 0.1 0.00 0.0 / 0.0
2.75 0.75 4,705.0 0.108 1,675.3 0.0 2,900.51 2;900.5 " 0.1
3 1 5,009.2 0.115 304.2 0.0 1,214.30 4,114.8 0.1
4 2 7,221.8 0.166 2,212.6 0.1 6,115.51 10,230.3 0.2
f
i
I
1
i
Water Quality Pond 1 Calculations
Stage-Storage(VOLUME) Page 1 of 1 Printed 1/16/2009 7:46 AM

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r
POND STAGE-STORAGE DATA
Vag Shelf Volumes
I Project SECU -Swan Quarter
Project No. 102-08
I Pond No. 1
Date 13-Jan-09
Incremental Incremental Incremental Incremental Cumulative Cumulative
Contour ID Stage Area Area Area Area volume volume volume volume
[sq.ft. acres s , ft. acres cu.ft acre-ft cu.ft acre-ft
-3 0 294.1 0.007 294.1 0.0 0.0 0.0 0.0 0.0
-2 1 506.1 0.012 212.0 0.0 400.1 0.0 400.1 0.0
.1 2 750.1 0.017 244.0 0.0 628.1 0.0 1,028.2 0.0
0 3 1,026.1 0.024 276.0 0.0 888.1 0.0 1,916.3 0.0
1 4 1,334.1 0.031 308.0 0.0 1,180.1 0.0 3,096.4 0.0
........................
1.5 4.5 1,500.0 0.034 165.9 0.0 708.5 00 a904.9 0.0
2 5 1 2,442.5 0.056 1 942.5 0.0 1 985.6 0.0 4,790.6 0.0
2.5 5.5 3,545.3 0.081 1,102.8 0.0 1,497.0 0.0 &287.6.J<: 0.1
t
1
Water Quality Pond 1 Calculations
Vag Shelf Volumes 'Page 1 of 1 Printed 1/15/2009 4:16 PM

Water Quality Basin Dewatering Time Calculations
r
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 2
Date 13-Jan-09
f Volume provided above orifice 2,901 cubic feet
Surface Area of Basin 4,705 square feet
Maximum head of water above dewatering hole 0.75 feet
Orifice coefficient 0.60
Diameter of each hole 0.75 inches
Number of holes 1
Discharge rate 0.013 cfs
Cross sectional area of each hole = 0.003 square feet
Cross sectional area of each hole = 0.4 square inches
Cross sectional area of dewatering hole(s) = 0.003 square feet
Cross sectional area of dewatering hole(s) = 0.4 square inches
Dewatering time for basin = 2.62 days
20

f
r
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve v9.1
Hyd. No. 1
` Pre-Dev Basin 1
Description A B C Totals
Sheet Flow
Manning's n-value = 0.150 0.011 0.011
Flow length (ft) = 186.0 0.0 0.0
Two-year 24-hr precip. (in) = 4.18 0.00 0.00
Land slope (%) = 0.20 0.00 0.00
Travel Time (min) = 35.38 + 0.00 + 0.00 = 35.38
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 0.50 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 1 .14 0.00 0.00
Travel Time (min) = 2.19 + 0.00 + 0.00 = 2.19
Channel Flow
X sectional flow area (sgft) = 0.00 0.00 0.00
Wetted perimeter (ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
` Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) = 0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
` Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 37.57 min
21

Hydrograph Report
Hydraflow Hydrographs by Intelisolve v9.1 Monday,Jan 19,2009
Hyd. No. 1
Pre-Dev Basin 1
` Hydrograph type = SCS Runoff Peak discharge = 0.357 cfs
Storm frequency = 1 yrs Time to peak = 742 min
Time interval = 7 min Hyd. volume = 2,105 cuft
Drainage area = 0.470 ac Curve number = 74
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = USER Time of conc. (Tc) = 38.00 min
Total precip. = 3.44 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Dev Basin 1
0 (cfs) Hyd. No. 1 -- 1 Year 0 (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
I
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 2 4 6 8 11 13 15 17 19 21 23 25
Hyd No. 1 Time (hrs)
-
2

Hydrograph Report
Hydraflow Hydrographs by Intelisolve v9.1 Monday,Jan 19,2009
Hyd. No. 2
Post-Dev Basin 1
Hydrograph type = SCS Runoff Peak discharge = 1 .813 cfs
Storm frequency = 1 yrs Time to peak = 717 min
Time interval = 1 min Hyd. volume = 3,745 cuft
Drainage area = 0.470 ac Curve number = 87
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = USER Time of conc. (Tc) = 5.00 min
Total precip. = 3.44 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Dev Basin 1
0 (cfs) 0 (cfs)
Hyd. No. 2 -- 1 Year
2.00 2.00
1.00 1.00
0.00 0.00
4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
-- Hyd No. 2 Time (hrs)
23

r Pond Report
( Hydraflow Hydrographs by Intelisolve v9.1 Friday,Jan 16,2009
Pond No. 1 - Wet Pond 1
Pond Data
Contours-User-defined contour areas. Conic method used for volume calculation. Begining Elevation= 7.00 If
I Stage/ Storage Table
Stage(ft) Elevation(ft) Contour area(sl Incr. Storage(cuff) Total storage(cutt)
0.00 7.00 294 0 0
1.00 8.00 506 395 395
2.00 9.00 865 678 1,073
3.00 10.00 1,266 1,059 2,132
4.00 11.00 1,736 1,495 3,627
5.00 12.00 3,030 2,353 5,980
6.00 13.00 5,009 3,978 9,958
7.00 14.00 7,222 6,081 16,039
Culvert/ Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
1
Rise (in) = 12.00 0.75 0.00 0.00 Crest Len(ft) = 8.00 0,00 0.00 0.00
! Span(in) = 12.00 0.75 0.00 0.00 Crest El.(ft) = 12.75 0.00 0.00 0.00
No. Barrels = 1 1 0 0 Weir Cal = 3.33 3.33 3.33 3.33
Invert El. (ft) = 9.25 12.00 0.00 0.00 Weir Type = Rect --- --- ---
Length (ft) = 43,00 0.00 0.00 0.00 Multi-Stage = Yes No No No
Slope(%) = 1.05 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Contour)
Multi-Stage = n/a Yes No No TW Ell (ft) 9.80
Note.Culven/Onfice outflows ate analyzed under inlet(is)and outlet loci control. Weir risers checked for orifice conditions(ic)and submergence(s).
)
l Stage(ft) Stage/Storage Elev(ft)
8.00 15.00
1
i
6.00 13.00
4.00 11.00
2.00 9.00
0.00 7.00
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000
Storage Storage(tuft)
2�

Hydrograph Report
Hydraflow Hydrographs by Intelisolve v9.1 Monday,Jan 19,2009
Hyd. No. 3
Wet Pond #1
Hydrograph type = Reservoir Peak discharge = 0.038 cfs
Storm frequency = 1 yrs Time to peak = 940 min
Time interval = 1 min Hyd. volume = 1 ,895 cuft
Inflow hyd. No. = 2 - Post-Dev Basin 1 Max. Elevation = 12.71 ft
Reservoir name = Wet Pond 1 Max. Storage = 8,799 cuft
Storage Indication method used. Wet pond routing start elevation = 12.00 ft.
Wet Pond #1
0 (cfs) Hyd. No. 3 -- 1 Year 0 (cfs)
2.00 2.00
i
1.00 1.00
0.00 0.00
0 3 6 9 12 15 18 21 24 27 30
— Hyd No. 3 — Hyd No. 2 Total storage used = 8,799 cuft Time (hrs)
25

Pond #1
1
i
Bouyancy Calculations
Wet Pond #1
Project: 102-08 Page 1 of 1
i Date: 1/15/09
Riser Width 2
Riser Length 2
Wall Thickness 0.67
Riser Depth 6.75
Base Volume 20.25 cf
Riser Inner Volume 27 Riser Inner Volume 27.00 cf
Riser Concrete Volume 48.30 Riser Concrete Volume 48.30 cf
Total Buoyant Force 4698.74 Total Buoyant Force 5962.34
i Concrete Weight 7245.05 Base Weight 3037.50
Riser Weight 7245.05
Desired Factor Of Safety 1.5 Total Resisting Force 10282.55
Total Weight Required 7048.11 Factor of Safety 1.72
Additonal Weight Required -196.94
Volume of Additional Concrete -3.49 CF
Base Width 4.5
Base Length 4.5
i Required Base Depth -0.17243 -2.06921 inches
Set Depth to min 1 feet
Page 1
2�v

Permit No.
( (m be nmvdtl by DWG)
(
(
��A$ WA TF,9Oc
( NCDENR
( STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
( WET DETENTION BASIN SUPPLEMENT
( This form must be filled out,printed and submitted.
( . The Required Items Checklist(Pad III)must be printed,filled out and submitted along with all of the required information.
( I. PROJECT INFORMATION
Project name Slate Employees Credit Union-Swan Quarter
( Contact person Parry E.Hilburn
Phone number (919)84BA399
( Date 1/1512008
( Drainage area number Pond#2
( II. DESIGN INFORMATION
( Site Characteristics
Drainage area 39,006 ry'
( Impervious area,post-development 23,453.00 ryt
%impervious 60.13 as /
( Design rainfall depth 1.5 in V
( Storage Volume: Non-SA Waters
Minimum volume required 113
( Volume provided rys
Storage Volume: SA Waters
( 1.5'runoff volume 2,882 ft3 v
( Pre-development 1-yr,24-hr runoff 381 rya
Post-development 1-yr.24-hf runoff 1,035 rya
( Minimum volume required 2,882 rya
( Volume provided 3,627 rys
Peak Flow Calculations
Is the preipost control of the lyr 24hr storm peak flow required? y (Y or N) /
1-yr,24-hr rainfall depth 3.4 in 1/
( Rational C,pre-development 0.25(unitless)
Rational C,post-development 0.68 limitless)
( Rainfall intensity:1-yr,24-hr storm 5.64 iNhr OK
Pre-development 1-yr,24-hr peak flow 1.30 ft3lsec
( Post-development 1-yr,24-hr peak flow 3.45 fl'Isec
k Pre/Post 1-yr,24-hr peak flow control 2.15 ry'Isec
Elevations
(. Temporary pool elevation 2.75 fmsl
Permanent pool elevation 2.00 fmsl
SHWT elevation(approx.at the pen.pool elevation) 1.40 first
l Top of 1 Oft vegetated shelf elevation 2.50 fmsl
Bottom of 1Oft vegetated shelf elevation 1.50 fmsl
Sediment cleanoul,top elevation(bottom of pond) -3.00 first
Sediment cleanout,bottom elevation A.00 first
Sediment storage provided 1.00 It
Is there additional volume stored above the stale-required temp.pool? n (Y or N)
Elevation of the lop of the additional volume 2.8 frost OK
Form SWannWel Detention Basin-Rev.S Paris 1.811.Design Summary,Page 1 of

f Permit No.
(to be Provee0 by DWO)
( 11. DESIGN INFORMATION
Surface Areas
Area,temporary pool 5,791 fh /
Area REQUIRED,permanent pool 2,610 it' ✓ /
SAIDA ratio 6.69(unflless)
Area PROVIDED,permanent pool,A.. 3,882 ft' OK
Area,bottom of 1 Oft vegetated shelf,A._,,,, 1,971 fl'
( Area,sediment cleanout,top elevation(bottom of pond),Ate,. 495 It'
( Volumes -/
( Volume,temporary pool 3,627 b'V OK
Volume,permanent pool,Vim„, 6,799 fl'
Volume,forebay(sum of forebays if more than one forebay) 1,429 II' /
f Forebay%of permanent pool volume 21.0%% QK
SAIDA Table Data
( Design TSS removal 90%
Coastal SAIDA Table Used? y (Y or N)
MountaiNPiedmont SAIDA Table Used? n (Y or N)
( SAIDA ratio 6.69(unifless)
Average depth(used in SAIDA table):
( Calculation option 1 used?(See Figure 10-2b) n (Y or N)
Volume,permanent pool,Vp,.m, fl3
Area provided,permanent pool,A.. tt'
( Average depth calculated If
Average depth used in SAIDA,d„,(Round to nearest 0.5ft) It
( Calculation option 2 used?(See Figure 10-2b) y (Y or N)
( Area provided,permanent pool,A, 3,882 fl' OK
Area,bottom of 1011 vegetated shelf,Ate,_, 1,971 fl' OK
( Area,sediment cleanoul,top elevation(bottom of pond),Ate, a 495 fl° OK
( 'Depth'(distance bhv bottom of 10f1 shelf and top of sediment) 4.50 It OK
Average depth calculated 3.19 ff OK
Average depth used in SAIDA,d„.,(Round to nearest 0.511) 3.2 It ,,/ OK
( Drawdown Calculations V
( Drawdown through odfice? y (Y or N) /
Diameter of odfice(if circular) 0.75 in v
( Area of orifice(if-non-circular) in'
( Coefficient of discharge(Co) 0.60(unitless)
Driving head(Ha) 0.75 fl
Drawdown through weir? n (Y or N)
Weir type (unifless)
(. Coefficient of discharge(C„.) (unifless)
Length of weir(L) It
Driving head(H) It
( Pre-development 1-yr,24-hr peak flow 1.30 ff'/sec OK
Post-development 1-yr,24-hr peak flow 3.45 fl'/sec OK
l
Storage volume discharge rate(through discharge office or weir) 0.01 fl'Isec
( OK,draws down in 2-5 days.
Storage volume drawdown time 3.28 days
t V OK,drawdown time is correct.
Additional Information
t Vegetated side slopes 3:1 OK
1 Vegetated shelf slope 10:1 OK
Vegetated shelf width 10.0 fl OK
Length of flowpath to width ratio 3:1 OK
Length to width ratio 2.9:1 OK
1. Trash rack for overflow 8 orifice? y (Y or N) OK
Freeboard provided 1.3 If OK
Vegetated filter provided? n (Y or N) OK
l Recorded drainage easement provided? n (Y or N) IacT P-E `1Qr"D PE�'L CONveVl�.1T(o,-1 wl SMnIQ.. D .
Capons all runoff at ultimate build-out? y (Y or N) OK
Drain mechanism for maintenance or emergencies Pond to be pumped for emergency,and maintenance purposes
1 Form SW401-Wet Detention Basin-Bev.5 Parts I.a II.Design Summary,Page 2 of 2
- 2 U Q

( Permit No.
(to be provided by OWO)
r Ill. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent,the agent may initial below. If a
requirement has not been met,attach justification.
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Pagel Plan
I ' fals Sheet No.
G1� 1. Plans If -50'or larger)of the entire site showing:
Design at ultimate build-out,
OH-site drainage(if applicable), f r4
5 V_frtVT5 l4 Z_ -Delineated drainage basins(include Rational C coefficient per basin), -5 CS "e/Wb L Strom
C 5102— -Basin dimensions, _ DAA L. - AtigP L-1
-Pretreatment system, Des fw- fJAU Tn VG✓ C,-94. S .
I High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way(ROW),
Overflow device, and
Boundaries of drainage easement.
l G 0 2 2. Partial plan(1"=30'or larger)and details for the wet detention basin showing:
-Outlet structure with trash rack or similar,
-Maintenance access,
-Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
-Basin cross-section,
-Vegetation specification for planting shelf,and
-Filter strip. 9'=A4W 97
C SI d*- 3. Section view of the wet detention basin(1"=20'or larger)showing:
-Side slopes,3:1 or lower,
-Pretreatment and treatment areas,and
-Inlet and outlet structures.
207 4. If the basin is used for sediment and erosion control during construction,clean out of the basin is specified
1 on the plans prior to use as a wet detention basin.
34-alp 5. A table of elevations,areas,incremental volumes&accumulated volumes for overall pond and for forebay,
to verify volume provided.
k 7-ib 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
,1 entire drainage area is stabilized.
PA,30 9-7 7. The supporting calculations.
EtWASM &. A copy of the signed and notarized operation and maintenance(0&M)agreement.
N I,� n7JA 9. A copy of the deed restrictions(if required).
OQCr. 1_ 1-1 10. A soils report that is based upon an actual field investigation,soil borings,and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin Rev.5 Part III.Required Items Checklist.Page 1 of
29

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WATER QUALITY POND #2
CALCULATIONS
i
Project Name
SECU - Swan Quarter
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Project Number
i
i 102-08
i
i Date
i 13-Jan-09
i
3rd revision
2nd revision
1st revision
30

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Water Quality Pond Drainage Area Data
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 2
Date 13-Jan-09
Total site area 39,006 square feet = 0.90 acres
Drainage area to and Other Drainage Area
Existing Proposed Change Existing Proposed
Impervious areas lsfl Isqs s s
On-site buildings 0 4,258 4,258 0 0
On-site streets 0 0 0 0 0
On-site parking 0 16,221 16,221 0 0
On-site sidewalks 0 1,738 1,738 0 0
Other on-site 0 1,236 1,236 0 0
Total off-site impervious 0 0 0 0 0
Total Impervious 0 1 23,453 23,453 0 0
Drainage area to end Other Drainage Area
Existing Proposed Change Existing Proposed
Non-impervious areas s s s s s
On-site grass/landscape 0 15,553 15,553 0 0
On-site woods 0 0 0 0 0
Other undeveloped 39,006 0 -39,006 0 0
Total off-site non-impervious 0 0 0 0 0
Total non-impervious 39,006 15,553 -23,453 0 0
Total Drainage Area 39,006 39,006 0 0 0
Percent Impervious 0.0 60.1 60.1 n/a n/a
Notes:
Water Quality Pond 2 Calculations
Site Drainage Area Data Page 1 of 1 Printed 1/15/2009 10:52 AM
3�

Water Quality Pond Surface Area Calculations
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 2
Date 13-Jan-09
Total on-site drainage area to pond 39,006 square feet
Total impervious area in drainage area 23,453 square feet
Average water depth of basin at normal pool 3.19 feet
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Location of site Swan Quarter
Site region Coastal
% Impervious cover 60.1 percent
If the site is in a coastal area, will a vegetative filter be used? No
Surface Area/Drainage Area Ratios:
i For a site in the Piedmont 2.3 percent
For a site in a Coastal County w/Vegetative Filter 4.8 percent
For a site in a Coastal County w/out Vegetative Filter 6.7 percent
Required surface area of pond:
For a site in the Piedmont 920.0 square feet
For a site in a Coastal County w/Vegetative Filter 1,870.0 square feet
For a site in a Coastal County w/out Vegetative Filter 2,610.0 Vsquare feet
Notes:
Water Quality Pond 2 Calculations
Pond Surface Area Calcs Page 1 of 1 Printed 1/15/2009 11:00 AM
32

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` Water Quality Pond Stormwater Runoff Volume Calculations
Project SECU - Swan Quarter
Project No. 102-08
i Pond No. 2
Date 13-Jan-09
Drainage area 39,006 square feet
Impervious area 23,453 square feet
Rainfall depth 1.50 inches
Percent Impervious 60.1 percent
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R(v)=0.05+0.009*(Percent impervious)
Runoff coefficient - R(v) 0.59 in/in
Runoff volume=(Design rainfall)*(R(v))*(Drainage area)
Runoff volume 2,882.3 cubic feet
Notes:
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Water Quality Pond 2 Calculations
Runoff Volume Calcs Page 1 of 1 Printed 1/15/2009 10:48 AM
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Water Quality Basin Dewatering Time Calculations
Project SECU - Swan Quarter
Project No. 102-08
Pond No. 2
i
Date 13-Jan-09
Volume provided above orifice 3,627 cubic feet
Surface Area of Basin 5,791 square feet
Maximum head of water above dewatering hole 0.75 feet
Orifice coefficient 0.60
Diameter of each hole 0.75 inches
Number of holes 1
Discharge rate 0.013 cfs
' Cross sectional area of each hole = 0.003 square feet
i Cross sectional area of each hole = 0.4 square inches
Cross sectional area of dewatering hole(s) = 0.003 square feet
Cross sectional area of dewatering hole(s) = 0.4 square inches
i
Dewatering time for basin = 3.28 days
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3�

TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve v9.1
Hyd. No. 8
Pre-Dev Basin 2
Description A B C Totals
Sheet Flow
Manning's n-value = 0.150 0.011 0.011
Flow length (ft) = 186.0 0.0 0.0
Two-year 24-hr precip. (in) = 4.18 0.00 0.00
Land slope (%) = 0.20 0.00 0.00
Travel Time (min) = 35.38 + 0.00 + 0.00 = 35.38
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 0.50 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 1 .14 0.00 0.00
Travel Time (min) = 2.19 + 0.00 + 0.00 = 2.19
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter (ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) = 0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 37.57 min
3�

Hydrograph Report
Hydraflow Hydrographs by Intelisolve v9.1 Monday,Jan 19,2009
Hyd. No. 5
Pre-Dev Basin 2
Hydrograph type = SCS Runoff Peak discharge = 0.684 cfs
Storm frequency = 1 yrs Time to peak = 742 min
Time interval = 7 min Hyd. volume = 4,031 cuft
Drainage area = 0.900 ac Curve number = 74
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = USER Time of conc. (Tc) = 38.00 min
Total precip. = 3.44 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
I Pre-Dev Basin 2
0 (cfs) Hyd. No. 5 -- 1 Year 0 (cfs)
1.00 1.00
0.90 0.90
I 0.80 0.80
0.70 0.70
0.60 0.60
0.50 0.50
0.40 0.40
0.30 0.30
0.20 0.20
0.10 0.10
0.00 0.00
0 2 4 6 8 11 13 15 17 19 21 23 25
— Hyd No. 5 Time (hrs)
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Hydrograph Report
f Hydraflow Hydrographs by Irdelisolve v9.1 Monday,Jan 19,2009
Hyd. No. 6
Post-Dev Basin 2
Hydrograph type = SCS Runoff Peak discharge = 3.710 cfs
Storm frequency = 1 yrs Time to peak = 717 min
Time interval = 1 min Hyd. volume = 7,755 cult
Drainage area = 0.900 ac Curve number = 89
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = USER Time of conc. (Tc) = 5.00 min
Total precip. = 3.44 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Dev Basin 2
r 0 (cfs) Hyd. No. 6 -- 1 Year 0 (cfs)
4.00 4.00
I
f 3.00 3.00
I
2.00 2.00
1.00 1.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
— Hyd No. 6 Time (hrs)
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r Pond Report
( Hydraflow Hydrographs by Intelisolve v9.1 Friday,Jan 16,2009
! Pond No. 2 - Wet Pond #2
Pond Data
Contours-User-defined contour areas.Conic method used for volume calculation. Begining Elevation=7.00 ft
Stage/Storage Table
Stage(ft) Elevation(ft) Contour area(sgft) Incr.Storage(cuft) Total storage(cult)
I
0.00 7.00 495 0 0
1.00 8.00 767 626 626
2.00 9.00 1,274 1,010 1,636
3.00 10.00 1,770 1,515 3,151
4.00 11.00 2,330 2,043 5,194
5.00 12.00 3,882 3,073 8,267
6.00 13.00 6,375 5,077 13,344
7.00 14.00 9,262 7,773 21,117
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Culvert/Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise (in) = 12.00 0.75 0.00 0.00 Crest Len(ft) = 8.00 0.00 0.00 0.00
Span (in) = 12.00 0.75 0.00 0.00 Crest El. (ft) = 12.75 0.00 0.00 0.00
No.Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33
Invert El. (ft) = 9.00 12.00 0.00 0.00 Weir Type = Rect --- --- ---
Length(it) = 54.00 0.00 0.00 0.00 Multi-Stage = Yes No No No
Slope 1%) = 0.74 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Contour)
Multi-Stage = n/a Yes No No TW Elev.(it) = 10.60
i Note:Culvert/Onf ce ourflum are analyzed under Inlet(ic)and outlet foc)control. Weir risers checked for orifice conditions fic)and submergence(s).
( Stage(ft) Stage/Storage Elev(ft)
8.00 15.00
6.00 13.00
i
4.00 11.00
2.00 9.00
0.00 7.00
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000 22,000
Storage Storage(cuft)
4(

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Hydrograph Report
Hydratlow Hydrographs by Intelisolve v9.1 Monday,Jan 19,2009
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 0.560 cfs
Storm frequency = 1 yrs Time to peak = 728 min
Time interval = 1 min Hyd. volume = 5,144 cult
Inflow hyd. No. = 6 - Post-Dev Basin 2 Max. Elevation = 12.82 ft
Reservoir name = Wet Pond #2 Max. Storage = 12,430 cult
Storage Indication method used. Wet pond routing start elevation= 12.00 ft.
Wet Pond #2
(cfs) Hyd. No. 7 -- 1 Year Q (cfs)
4.00 4.00
3.00 3.00
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2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24
— Hyd No. 7 — Hyd No. 6 Total storage used = 12,430 cult Time (hrs)
Z

Pond #2
1
Bouyancy Calculations
Wet Pond#2
Project: 102-08 Page 1 of 1
Date: 9/30/08
Riser Width 2
Riser Length 2
Wall Thickness 0.67
Riser Depth 6.75
Base Volume 20.25 cf
Riser Inner Volume 27 Riser Inner Volume 27.00 cf
Riser Concrete Volume 48.30 Riser Concrete Volume 48.30 cf
Total Buoyant Force 4698.74 Total Buoyant Force 5962.34
Concrete Weight 7245.05 Base Weight 3037.50
Riser Weight 7245.05
Desired Factor Of Safety 1.6 Total Resisting Force 10282.55
Total Weight Required 7048.11 Factor of Safety 1.72
Additonal Weight Required -196.94
Volume of Additional Concrete -3.49 CF
Base Width 4?5
Base Length 4.6
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Required Base Depth -0.17243 -2.06921 inches
I Set Depth to min t feet
Page 1
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Hydrograph Summary Report Hydraflow Hydrographs by lntelisolve v9,1
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.357 7 742 2,105 ---- ------ ------ Pre-Dev Basin 1
2 SCS Runoff 1.813 1 717 3,745 ---- ------ ------ Post-Dev Basin 1
3 Reservoir 0.038 1 940 1,895 2 12.71 8,799 Wet Pond N1
5 SCS Runoff 0.684 7 742 4,031 ---- ------ ------ Pre-Dev Basin 2
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6 SCS Runoff 3.710 1 717 7,755 ---- ----- ------ Post-Dev Basin 2
7 Reservoir 0.560 1 728 5,144 6 12.82 12,430 Wet Pond N2
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SECU-SQ_BMP Design_.gpw Return Period: 1 Year Monday, Jan 19, 2009

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Hydrograph Summary Report Hydraflow Hydrographs by lntelisolve v9.1
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Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cuft) 00 (cuft)
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1 SCS Runoff 1.116 7 742 6,252 ---- ------ ------ Pre-Dev Basin 1
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2 SCS Runoff 4.023 1 717 8,690 ---- ------ ------ Post-Dev Basin 1
3 Reservoir 2.782 1 721 6,831 2 12.97 9,832 Wet Pond N1
5 SCS Runoff 2.138 7 742 11,971 ---- ------ ------ Pre-Dev Basin 2
6 SCS Runoff 7.931 1 717 17,393 ---- ----- ------ Post-Dev Basin 2
7 Reservoir 5.420 1 721 14,770 6 13.15 14,495 Wet Pond N2
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Hydrograph Summary Report
Hydraflow Hydrographs by Intelisolve v9.1
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Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cult) (Il) (cuft)
1 SCS Runoff 2.313 7 735 12,999 ---- ------ ------ Pre-Dev Basin 1
2 SCS Runoff 7.117 1 717 16,001 ---- ------ ----- Post-Dev Basin 1
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3 Reservoir 5.808 1 720 14,135 2 13.12 10,712 Wet Pond N1
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5 SCS Runoff 4.429 7 735 24,892 ---- ------ ------ Pre-Dev Basin 2
I 6 SCS Runoff 13.81 1 717 31,493 ---- ------ ---- Post-Dev Basin 2
7 Reservoir 6.106 1 723 28,860 6 13.61 18,070 Wet Pond H2
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•'1 ' DATE Page 1
1/1512009
PROJECT NAME PROJECT NO
SECU Swan Ommor 1D2 08
BY
PER
Storm Outlet Structure
FES No.= FES1 Oro/Olull- 062
Pipe Ola= 12 in VNto11= 1.05
am- 1.99 tls V= 4.2 Ips
Olull= 3.19 ris
Mull= 4061ps
From Fig 806.b1 Zone I
From Fig.8.06.b 2 D50 3 in
D.. 45 in
t
R'pmp Class = A
Apron Ri vkness = 4 in 1
- Apron Longer = 3D-k- 15 e,aeem 1U 1OE OF .SIOpF>
Apron Width 3.Dm = 3 X(required)
r
I
5S

. +DATE Page 2
n 1I15/21)09
PROJECT NAME PROJECT NO
SECU-Swan Opener 102-08
BY
PER
i
Storm Outlet Structure
I FES No= FES-8 0,NOW- 0a6
Pipe Dian 12 in VNVI= 097
Oro= 208 cfs V= 56 fps
OMI= 451 ds
Vfull= 514 fps
From Fig.806.b.I. Zone 1
F,o,,Fig.60662: D. = 3 In
Danz 4.5 In
n Riprap Class = A
Apron Thickness = 12 p,.
Apron Length - i94-��,rlT'-Map � TOE �ti< Sl �
Apron Width=3.Dia f 3 ( wred)
I
tt f ue -k, DATE
915/2008
( PROJECT NAME PROJECT NO
SECU Swan OuaM1er 102 08
BY
PER
( Storm Outlet Structure
FES No.= FES-11 OmlOfull= 062
Pipe DIa= 12 in VNIUII= 1.05
Cho= 1.56 ch V= 3E fps
I OtoII- 2.52 cis
VVI= 3.21 fps
I From Fig.8 06 b 1 Zone = 1
From Fig.806 b.2Y. Dso = 3 In
Da. = 4.5 in
Riprap Class = A
( - a Apron Thickness = 12 in
` Apron Length = 4.0 11
( x Apron Width=3xD.a = 3 If(required)
)
1
I
I

DATE Page
/ 1/15/2009
PROJECTNAME PROJECT NO
SECU-Swan Quarter 102-08
BY
PEH
1
Storm Outlet Structure
FES No.= FES-15 Ora/OMI= 001
Pipe DIa= 12 In VNfWl= 0.32
Oro= 002 cis V= 1.5 fps
OU 3.60 Cis
Vfoll= 4.60 fps
(
From Fig.8.06.b.1: Zone 1
.. m.Fig 006 b2 OSC 3 In
Duct 4 5
n Rii Class - A
_ l { Apron Thickness 12 In
h APron Lengib 00 it
Apron Width=3xDie = 3 M1(required)
DATE
1/15/2009
PROJErCT NAME PROJECT NO
I SECU Swan Quarter 102-08
BY
PEH
( Storm Outlet Structure
FES Na.= FES-16 Ora/Olull= 0.11
Pipe Dian: 12 in VNI0 067
Oro= 0.34 cis V= 26 fps
Qlull- 306 cis
Vlull= 3 90 fps
From Fig.8.06.b.I Zane = 1
From Fig.8.06.b.2. Dso = 3 In
DMA% - 45 in
r 'a Fill Class A
Apron Thl@ness 12 in
z, Apron Length = 4.0 X
Apron Width=3xDia 3 V(required)
t
ft
l
1 ��

I
a 1 a '4� DATE Lags 3
101612006
PROJECT NAME PROJECT NO
/ SECU Seem Ouarlar _ IO2-08
BY
PEH
Storm Outlet Structure
FES No.= 30'CMP Om1O1uIl- 082
Pipe Dia= 30 in VNWII- L11
Ors- 15.01 ds V= 4.2fps
Olull= 1034 rJs
V1u1I= 374 fps
From Fig.806 b.1'. Zone _ 1
From Fig.8 06 a Dso 3 In
Din. _ 45 In
- Prep Class A
p Apron Thickness 12 in
IM Apron Length 100 M1
J Apron Width=3x01a - 7.5 fl(,egmretl)
r t' '• _4 DATE
1 9/5/2008
PROJECTNAME PROJECT NO
SECU Swan Ouaner 102-08
BY
PER
Storm Outlet Structure
FES Na.= 55'CMP O1011_ 012
Pipe 0', 15 in VNIWI. 061
Oro= 0.66 els V= 301,
Droll= 5.56 cls
VWIIin 4.53fps
Fram FigeOb.b.t'. Zone 1
From Fig.8.06 b.2. Daa 3 In
DM0.t _ 4.5 in
1 Riprap Class A
Apron Tlllcss 12 in
1 1 Apron Length so fi
Apron Width=3%Dia 375 il reeuir.G)
5Y1

r
Sediment Basin Calculations
SEDIMENT TRAP 1
l
Peak Inflow O=CxIxA
C value 1 0.35 Junimproved cleared area
intensi 10 ear 8.27
Drainage area ac 0.88
Peak Inflow cfs 2.55
Surface Area A=0.Otx
Peak inflow 10 = 2.55 cfs
Surface Area 0.03 ac
Calculation(A)= 1,110 sf
Basin Shape
Ensure flow length to basin width ratio is realer than 2:1
ft Calculated Ratio= len th = 47.11 width ft = 23.55 1 IxW = 1,110
used Ratio= length ft= 54,00 width fl = 1 28,00 1 LxW - 1.512
Basin Volume
Required Volume for
I Disturbed area (ac) 0.88 basins 3600 cf per 3,168 CF
ac of disturbed area=
Basin Dimensions
Top of water storage Bottom Surface area Water storage Storage
length N width tt length ft width ft s tle ih ft volume
54.00 28.00 42 16 1 31 631 3 3168
Top of basin Freeboard depth(fl) Total Depth Weir Width
length tt width=ftd tt ft
60 34 1.5 4.5 10
f
i
1 012 Sediment Trap Design 10/1/2008,2:39 PM
s 1

r
Sediment Basin Calculations
(
SEDIMENT TRAP 2
Peak Inflow O=CxlxA
C value 0.35 unimproved cleared area
intensity 10 ear 8.27
Drainage area ac 1.07
Peak Inflow cfs 3.10
Surface Area A=0.01x
Peak inflow 10 = 3.10 cis
Surface Area 0.03 ac
Calculation A= 1,349 sf
Basin Shape
Ensure flow Ien th to basin width ratio is realer than 2:1
Calculated Ratio= length tt= 51.94 width it = 25.97 LXW = 1 349
used Ratio= length = 60.00 width ft = 30.00 lxW = 1 800
ft
( Basin Volume
I Required Volume for
Disturbed area(ac) 1 W basins 3600 ct per 3,852 CF
I ac of disturbed area-
Basin Dimensions
Top 01 water slora a Bottom Sudace area W star storage Storage
length tt width ft length ft width ft s de th tt volume
60.00 30.00 48 18 38 631 3 3,888
To of basin Freeboard depth(tt) Total Depth Weir Width
Ien ih tt width tt ry ry
66 1 36 1 1.5 4.5 10
l
l
i
1 011 Sediment Trap Design 10/l/2008.2:34 PM
UO

Grass Swale #1
2-yr Storm
Given input Data:
Shape . . . . . . . . . . . . . . . . . . . . . . . . Trapezoidal
solving for . . . . . . . . . . . . . . . . . . . . . Depth of Flow
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 0.9900 cfs
slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0090 ft/ft
manning's n . . . . . . . . . . . . . . . . . . . . . 0.0330
Height . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0000 ft
Bottom width . . . . . . . . . . . . . . . . . . . . 0.0000 ft
Left slope . . . . . . . . . . . . . . . . . . . . . . 0.2500 ft/ft (v/H)
Right slope . . . . . . . . . . . . . . . . . . . . . 0.2500 ft/ft (v/H)
computed Results:
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.4118 ft
velocity . . . . . . . . . . . . . . . . . . . . . . . . 1.4597 fps
Full Flowrate . . . . . . . . . . . . . . . . . . . 10. 5493 cfs
Flow area . . . . . . . . . . . . . . . . . . . . . . . 0.6782 ft2
Flow perimeter . . . . . . . . . . . . . . . . . . 3.3955 ft
Hydraulic radius . . . . . . . . . . . . . . . . 0.1997 ft
Top width . . . . . . . . . . . . . . . . . . . . . . . 3.2942 ft
Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0000 ft2
Perimeter . . . . . . . . . . . . . . . . . . . . . . . 8.2462 ft
Percent full . . . . . . . . . . . . . . . . . . . . 41.1770
critical information
critical depth . . . . . . . . . . . . . . . . . . 0.3282 ft
critical slope . . . . . . . . . . . . . . . . . . 0.0302 ft/ft
critical velocity . . . . . . . . . . . . . . . 2.2978 fps
critical area . . . . . . . . . . . . . . . . . . . 0.4309 ft2
critical perimeter . . . . . . . . . . . . . . 2.7064 ft
critical hydraulic radius . . . . . . . 0.1592 ft
critical top width . . . . . . . . . . . . . . 2 .6256 ft
specific energy . . . . . . . . . . . . . . . . . 0.4449 ft
Minimum energy . . . . . . . . . . . . . . . . . . 0.4923 ft
i Froude number . . . . . . . . . . . . . . . . . . . 0. 5672
Flow condition . . . . . . . . . . . . . . . . . . Subcritical
i

i
Grass Swale #1
10-yr Storm
Given input Data:
Shape . . . . . . . . . . . . . . . . . . . . . . . . Trapezoidal
solving for Depth of Flow
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 2.4700 cfs
slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0090 ft/ft
manning' s n . . . . . . . . . . . . . . . . . . . . . 0.0300
Height . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0000 ft
Bottom width . . . . . . . . . . . . . . . . . . . . 0.0000 ft
Left slope . . . . . . . . . . . . . . . . . . . . . . 0.2500 ft/ft (v/H)
Right slope . . . . . . . . . . . . . . . . . . . . . 0.2500 ft/ft (v/H)
computed Results:
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 0. 5598 ft
velocity . . . . . . . . . . . . . . . . . . . . . . . . 1.9705 fps
Full Flowrate . . . . . . . . . . . . . . . . . . . 11.6042 cfs
Flow area . . . . . . . . . . . . . . . . . . . . . . . 1.2535 ft2
Flow perimeter . . . . . . . . . . . . . . . . . . 4.6162 ft
r Hydraulic radius . . . . . . . . . . . . . . . . 0.2715 ft
Top width . . . . . . . . . . . . . . . . . . . . . . . 4.4784 ft
r area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.0000 ft2
Perimeter . . . . . . . . . . . . . . . . . . . . . . . 8.2462 ft
Percent full . . . . . . . . . . . . . . . . . . . . 55.9797
! critical Information
critical depth . . . . . . . . . . . . . . . . . . 0.4731 ft
critical slope . . . . . . . . . . . . . . . . . . 0.0221 ft/ft
r critical velocity . . . . . . . . . . . . . . . 2.7588 fps
critical area . . . . . . . . . . . . . . . . . . . 0.8953 ft2
Critical perimeter . . . . . . . . . . . . . . 3.9013 ft
Critical hydraulic radius . . . . . . . 0.2295 ft
critical top width . . . . . . . . . . . . . . 3.7849 ft
Specific energy . . . . . . . . . . . . . . . . . 0.6201 ft
Minimum energy . . . . . . . . . . . . . . . . . . 0.7097 ft
Froude number . . . . . . . . . . . . . . . . . . . 0.6566
Flow condition . . . . . . . . . . . . . . . . . . subcritical
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. § 5

Grass Swale rig
2-yr Storm
Given Input Data:
Shape . . . . . . . . . . . . . . . . . . . . . . . . Trapezoidal
solving for Depth of Flow
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 1.0300 cfs
slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0075 ft/ft
manning' s n . . . . . . . . . . . . . . . . . . . . . 0.0330
Height . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0000 ft
Bottom width . . . . . . . . . . . . . . . . . . . . 0.0000 ft
Left slope . . . . . . . . . . . . . . . . . . . . . . 0.2000 ft/ft (v/H)
Right slope . . . . . . . . . . . . . . . . . . . . . 0.2000 ft/ft (v/H)
Computed Results:
De th . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3967 ft
velocity . . . . . . . . . . . . . . . . . . . . . . . . 1.3091 fps
Full Flowrate . . . . . . . . . . . . . . . . . . . 12.1239 cfs
Flow area . . . . . . . . . . . . . . . . . . . . . . . 0.7868 ft2
Flow perimeter . . . . . . . . . . . . . . . . . . 4.0454 ft
Hydraulic radius . . . . . . . . . . . . . . . . 0.1945 ft
Top width . . . . . . . . . . . . . . . . . . . . . . . 3.9669 ft
Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.0000 ft2
Perimeter . . . . . . . . . . . . . . . . . . . . . . . 10. 1980 ft
Percent full . . . . . . . . . . . . . . . . . . . . 39.6688
critical Information
Critical depth . . . . . . . . . . . . . . . . . . 0.3050 ft
critical slope . . . . . . . . . . . . . . . . . . 0.0305 ft/ft
critical velocity . . . . . . . . . . . . . . . 2.2149 fps
Critical area . . . . . . . . . . . . . . . . . . . 0.4650 ft2
t critical perimeter 3.1101 ft
critical hydraulic radius . . . . . . . 0.1495 ft
critical top width 3.0497 ft
specific energy . . . . . . . . . . . . . . . . . 0.4233 ft
Minimum energy . . . . . . . . . . . . . . . . . . 0.4574 ft
Froude number . . . . . . . . . . . . . . . . . . . 0. 5182
Flow condition Subcritical
. . . . . . . . . . . . . . . . . .
i
ce�

Grass Swale #2
10-yr Storm
Given Input Data:
Shape . . . . . . . . . . . . . . . . . . . . . . . . . Trapezoidal
Solving for Depth of Flow
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 2.2800 cfs
Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0075 ft/ft
manning' s n . . . . . . . . . . . . . . . . . . . . . 0.0300
Height . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0000 ft
Bottom width . . . . . . . . . . . . . . . . . . . . 0.0000 ft
Left slope . . . . . . . . . . . . . . . . . . . . . . 0.2000 ft/ft (v/H)
Right slope . . . . . . . . . . . . . . . . . . . . . 0.2000 ft/ft (v/H)
Computed Results:
Depth 0. 5156 ft
velocity . . . . . . . . . . . . . . . . . . . . . . . . 1.7151 fps
Full Flowrate . . . . . . . . . . . . . . . . . . . 13. 3363 cfs
Flow area . . . . . . . . . . . . . . . . . . . . . . . 1. 3294 ft2
Flow perimeter . . . . . . . . . . . . . . . . . . 5 . 2584 ft
Hydraulic radius . . . . . . . . . . . . . . . . 0. 2528 ft
Top width . . . . . . . . . . . . . . . . . . . . . . . 5 .1563 ft
Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.0000 ft2
Perimeter 10.1980 ft
Percent full . . . . . . . . . . . . . . . . . . . . 51. 5630
critical Information
critical depth . . . . . . . . . . . . . . . . . . 0.4191 ft
critical slope . . . . . . . . . . . . . . . . . . 0.0227 ft/ft
critical velocity . . . . . . . . . . . . . . . 2 . 5965 fps
critical area . . . . . . . . . . . . . . . . . . . 0.8781 ft2
critical perimeter . . . . . . . . . . . . . . 4.2737 ft
critical hydraulic radius . . . . . . . 0.2055 ft
critical top width . . . . . . . . . . . . . . 4.1907 ft
specific energy . . . . . . . . . . . . . . . . . 0.5613 ft
Minimum energy . . . . . . . . . . . . . . . . . . 0.6286 ft
Froude number . . . . . . . . . . . . . . . . . . . 0. 5955
Flow condition . . . . . . . . . . . . . . . . . . Subcritical
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CULVERT-1
(30" RCP)
10-YEAR STROM
Given Input Data:
shape . . . . . . . . . .
p • • . • . • . . . . . . . . . . Circular
solving for . . . . . . . . . . . . . . . . . . . . . Depth of Flow
Diameter . . . . . . . . . . . . . . . . . . . . . . . . 2 . 5000 ft
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 18.2600 cfs
slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0020 ft/ft
Man m ng 's n . . . . . . . . . . . . . . . . . . . . . 0.0130
Computed Results:
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0388 ft
Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9087 ft2
wetted Area . . . . . . . . . . . . . . . . . . . . . 4.2863 ft2
Wetted Perimeter . . . . . . . . . . . . . . . . 5.6342 ft
Perimeter
7.8540 ft
Velocity . . . . . . . . . . . . . . . . . . . . . . . . 4.2601 fps
Hydraulic Radius . . . . . . . . . . . . . . . . 0.7608 ft
Percent Full . . . . . . . . . . . . . . . . . . . . 81. 5518 %
Full flow Flowrate . . . . . . . . . . . . . . 18. 3434 cfs
Full flow velocity . . . . . . . . . . . . . . 3 .7369 fps
critical Information
Critical depth . . . . . . . . . . . . . . . . . . 1.4519 ft
critical slope 0.0048 ft/ft
critical velocity . . . . . . . . . . . . . . . 6.1710 fps
critical area 2 .9590 ft2
Critical perimeter . . 4. 3307 ft
Critical hydraulic radius . . . . . . . 0.6833 ft
Critical top width . . . . . . . . . . . . . . 2. 5000 ft
specific energy . . . . . . . . . . . . . . . . . 2.2386 ft
i Minimum energy . . . . . . . . . . . . . . . . . . 2.1778 ft
Froude number . . . . . . . . . . . . . . . . . . . 0. 5942
Flow condition . . . . . . . . . . . . . . . . . . subcritical
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CULVERT-2
(15" RCP) C 30" 7a BE �D1- �Do7�
10-YEAR STROM
Given Input Data:
shape . . . . . . . . . . . . . . . . . . . . . . . . . . . Circular
solving for Depth of Flow
Diameter . . . . . . . . . . . . . . . . . . . . . . . . 1.2500 ft
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 0.6600 cfs
slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0020 ft/ft
Manning' s n . . . . . . . . . . . . . . . . . . . . . 0.0130
Computed Results:
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.4063 ft
Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2272 ft2
wetted Area . . . . . . . . . . . . . . . . . . . . . 0. 3459 ft2
wetted Perimeter . . . . . . . . . . . . . . . . 1. 5166 ft
Perimeter . . . . . . . . . . . . . . . . . . . . . . . 3.9270 ft
velocity . . . 1.9082 fps
Hydraulic Radius . . . . . . . . . . . . . . . . 0.2281 ft
Percent Full . . . . . . . . . . . . . . . . . . . . 32. 5020
Full flow Flowrate . . . . . . . . . . . . . . 2.8889 cfs
Full flow velocity . . . . . . . . . . . . . . 2 . 3541 fps
Critical Information
Critical depth . . . . . . . . . . . . . . . . . . 0. 3173 ft
Critical slope . . . . . . . . . . . . . . . . . . 0.0052 ft/ft
Critical velocity . . . . . . . . . . . . . . . 2.6924 fps
Critical area . . . . . . . . . . . . . . . . . . . 0.2451 ft2
Critical perimeter . . . . . . . . . . . . . . 1.3201 ft
Critical hydraulic radius . . . . . . . 0.1857 ft
critical top width . . . . . . . . . . . . . . 1.0880 ft
specific energy . . . . . . . . . . . . . . . . . 0.4629 ft
Minimum energy . . . . . . . . . . . . . . . . . . 0.4760 ft
Froude number . . . . . . . . . . . . . . . . . . . 0.6190
Flow condition . . . . . . . . . . . . . . . . . . subcritical

EXISTING 24" CMP
10-YEAR STROM
Given Input Data:
Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . Circular
solving for Depth of Flow
r Diameter . . . . . . . . . . . . . . . . . . . . . . . . 2.0000 ft
Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 1.9500 cfs
Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0170 ft/ft
Manning' s n . . . . . . . . . . . . . . . . . . . . . 0.0200
computed Results:
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.4308 ft
Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1416 ft2
wetted Area . . . . . . . . . . . . . . . . . . . . . 0.4972 ft2
wetted Perimeter . . . . . . . . . . . . . . . . 1.9305 ft
Perimeter . . . . . . . . . . . . . . . . . . . . . . . 6.2832 ft
velocity
Hydraulic Radius . . . . . . . . . . . . . . . . 0.2576 ft
ps
Percent Full 21. 5389
Full flow Flowrate . . . . . . . . . . . . . . 19.1724 cfs
Full flow velocity . . . . . . . . . . . . . . 6. 1028 fps
Critical Information
Critical depth . . . . . . . . . . . . . . . . . . 0.4844 ft
critical slope . . . . . . . . . . . . . . . . . . 0.0106 ft/ft
Critical velocity . . . . . . . . . . . . . . . 3.3205 fps
critical area . . . . . . . . . . . . . . . . . . . 0. 5873 ft2
critical perimeter . . . . . . . . . . . . . . 2.0581 ft
Critical hydraulic radius . . . . . . . 0.2853 ft
critical top width . . . . . . . . . . . . . . 1.7136 ft
specific energy . . . . . . . . . . . . . . . . . 0.6698 ft
Minimum energy . . . . . . . . . . . . . . . . . . 0.7266 ft
t Froude number . . . . . . . . . . . . . . . . . . . 1.2573
Flow condition . . . . . . . . . . . . . . . . . . supercritical
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I
SEEDING & MULCHING
SEEDBED PREPARATION
THE CONTRACTOR SHALL CUT AND DISPOSE OF WEEDS OR OTHER UNACCEPTABLE GROWTH ON
THE AREAS TO BE SEEDED, UNEVEN OR ROUGH AREAS SHALL BE SHAPED AND SMOOTHED TO PROVIDE
FOR EFFECTIVE SEEDING AND EASE OF MOWING. THE SOIL SHALL BE SCARIFIED TO A DEPTH OF NOT
LESS THAN 5 INCHES. CLODS SHALL BE BROKEN AND THE TOP 3-4 INCHES OF THE SOIL SHALL BE
WORKED INTO A SEEDBED BY THE USE OF PULVERIZERS, DRAGS, OR HARROWS, THE PREPARATION OF
SEEDBEDS SHALL NOT BE DONE WHEN THE SOIL IS FROZEN OR EXTREMELY WET.
SOIL AMENDMENTS
APPLY LIME AND FERTILIZER ACCORDING TO SOIL TESTS, OR APPLY 3,000-5,000 LB/ACRE
GROUND AGRICULTURAL LIMESTONE (USE THE LOWER RATE ON SANDY SOILS) AND 1,000 LB/ACRE
10-10-10 FERTILIZER.
MULCHING
ANCHOR APPLY
TRAW BY TACKINGE GRAIN WI H ASPHALT, NEMNG,OR EQUIVALENT
O NG, OR BY CRIMPING
COVER OF WITH ER SUITABLE
A MULCHMULCH.
ANCHORING TOOL A DISK WITH BLADES SET NEARLY STRAIGHT CAN BE USED AS A MULCHING
TOOL.
MAINTENANCE
IF GROWTH IS LESS THAN FULLY ADEQUATE, REFERTIUZE IN THE SECOND YEAR, ACCORDING TO
SOIL TESTS OR TOPDRESS WITH 500 LB/ACRE 10-10-10 FERTILIZER. MOW AS NEEDED WHEN
` SERICEA IS OMITTED FROM THE MIXTURE RESEED, FERTILIZE, AND MULCH DAMAGED AREAS
( IMMEDIATELY.
PERMANENT SEEDING
AMOUNT/ TIME OF FERTILIZATION / 10D0 SF.
GRASS TYPE 1ODO SF. SEEDING INITIAL MAINTENANCE
BERMUOA, COMMON 1-2 LEIS. APR. THRU .DINE 25 LEIS. f0-10-10 MARCH - APRIL EACH 4-8 MEEKS AUG. - SEPT.
12 LBS. 10-10-10 1-2 LEIS. N. 12 LBS. 10-113-10
FESCUE, TALL 5-7 LBS. SEPT. THRU OCT. 25 LBS. 10-10-10 FEE. - MARCH MAY & DEC. SEPT. - OCT.
(KENTUCKY 31) FEE. THRU OCT. 12 LBS. 10-10-10 1/2 TO 1 LB. N. 12 LBS. 10-10-10
SERICEA
IESPEDEZA (SLOPES 1-2 LDS. MARCH THRU APR, 25 LBS. 10-10-10 FEB. - MARCH 1/2 TO 1 LB. N. NA

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Soil & Environmental Consultants , PA
11010 Raven Ridge Road • Raleigh, North Carolina 27614 • Phone:[phone] • Fax: [phone]
www.SandEC.cotn
September 4, 2008
( S&EC Project #: 11141.S2
Geotechnologies, Inc P.A.
Attn: Ernie Stitzinger
3200 Wellington Court Suite 108
Raleigh, NC 27615
Re: Detailed Soils Evaluation at proposed State Employees Credit Union located adjacent
to Hwy 264 in Swan Quarter, Hyde County, NC.
Dear Mr. Stitzinger:
I
Soil & Environmental Consultants, PA (S&EC) has performed a detailed soil evaluation
in the proposed stonnvater infiltration area at the site mentioned above. A map showing
the location of the proposed stormwater infiltration area was provided to us by the project
engineer. At the indicated locations, the following activities were performed: a profile
description to seven feet (or as deep as possible with hand augers), estimation of
permeability, hydraulic conductivity, and seasonal high water table based on soil color,
and apparent (observed) water table measurement (groundwater rise in auger holes). The
purpose of this evaluation was to provide you with additional information for designing a
stormwater infiltration device. The following is a brief report of the methods utilized in
this evaluation and the results obtained.
( SoillSite Evaluation
A site evaluation was performed by Walter Cole, Sarah Menser(NCLSS and NCSSIT) to
I acquire the information you needed. The eva uatlon was performed by making hand
auger borings to a depth of seven feet at four locations which were located with a GPS
receiver and are shown on the attached map and identifying and recording the soil
morphological conditions at those locations in order to develop soil profile descriptions,
which are also included with this report and shown of the attached map.
Seasonal high Water Table );valuation
Under current regulations, the bottom of any infiltration device shall not be placed in
locations with less than 2 feet separation between the bottom of the infiltration device and
I the seasonal high groundwater [I5A NCAC 02H .1008 (d) (3)],underlying impervious
soil horizon, or bedrock (4 foot separation is recommended). For Soil Borings 1-4, the
seasonal high water table based on soil morphology(munsell color), was less than 12
inches from the soil surface. The apparent (observed) water table in all three borings at
one hour was 72 inches, however this is just a "snap-shot"measurement the reality is
that the actual seasonal high water table is most likely deeper than what is serve
Soil color, especially with existing agricultural ditching, ut s a ower tan was 1s
Chu lotte Office; OLnsboro OKce:
236 LePhillip Court,Suitc C 3817-E Lawndale Drive
Concord,NC 28025 Greensboro,NC 27455
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
Z Z

observed by apparent water table. The only way to accurately determine the seasonal high
w put m test wells, monitor the site, and perform a water table
assessment, and this service can be provided by our firm if requested.
Based on our findings, the soil conditions on-site seem unsuitable for an infiltration
device with respect to seasonal high water table, however it may have favorable
characteristics for a wet detention pond.
Permeability/Hydraulic Conductivity Estimation
Under current regulations, soils underlying a stormwater infiltration device must have a
minimum infiltration rate of 0.52 inches per hour or greater [15A NCAC 02H .1008 (d)
(6)]. Soil borings 2 -4 revealed a silt loam surface horizon and a silty clay loam
subsurface horizon which is slowly permeable soils with estimated hydraulic conductivity
ranges form .01-.14 inches/hour which is well below the threshold of 0.52 inches/hour.
Please refer to the enclosed map and soil profile descriptions for more information.
Although on-site saturated hydraulic conductivity measurements would be needed to
definitively show that these layers are below the 0.52 inches per hour threshold, we feel
strongly that any testing will reveal that these soils will not meet the threshold, and that if
the water table depth were favorable which it is not, the excavation of the soil horizons
and replacement with sand will be necessary and must be proposed to NCDWQ for then)
to approve on a case-by-case basis. All of these estimates obtained from one or more of
the following: Hyde County Soil Survey"Physical & Chemical Properties of the Soil -
Permeability'; and/or USDA-NRCS (United States Department of Agriculture -Natural
Resource Conservation Service) Roanoke official series description, and/or"NRCS Field
Book for Describing & Sampling Soils" and since the rules require a minimum hydraulic
conductivity of 0.52 inches per hour or more, the permeability estimates were converted
to conductivity on the profile description tables.
In conclusion, the soil conditions on-site do not seem favorable for a stormwater
infiltration device with respect to soil permeability/hydraulic conductivity, and the
seasonal high water table, however the site may be suitable and have favorable conditions
for an alternative stormwater treatment device such as a wet detention pond.
1 Soil & Environmental Consultants, PA is pleased to be of service in this matter and we
look forward to assisting in the successful completion of the project. Please feel free to
call with any questions or comments.
'�3

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Sincerely,
Tr
Y _
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walter Cole
NC Licensed Soil Scientist t11267
File:
Figure 1: USGS Quadrangle Map
I Figure 2: Hyde County Soil Survey Map
Figure 3: Stormwater Boring Map
Soil Profile Descriptions

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Soil & Environmental Consultants, PA
11010 Raven Ridge Road Raleigh, North Carolina 27614 • Phone:[phone] • Fax: [phone]
Nvww.SandEC.corn
i
September 4, 2008
S&EC Project # 11141.S2
GeoTechnologies, Inc P.A.
Attn: Ernie Stitzinger
3200 Wellington Court Suite 108
( Raleigh, NC 27615
Re: Preliminary Wetland Delineation
( Swan Quarter SECU Site
( Hyde County,NC
Dear Mr. Stitzinger:
In August, 2008, S&EC personnel traversed the subject property to determine the presence of
potential wetlands. The site is located on the north side of US 264, as shown on the attached
i USGS Quad map(Figure 1) and Hyde County Soil Survey (Figure 2).
Wetlands:
( Potential wetland areas on the site were evaluated for the presence of hydric soils and evidence
( of hydrology and vegetation. In these areas, hydrologic proof includes the existence of hydric
soils with oxidized root channels in the upper 12 inches of the soil profile, water borne deposits,
l drift lines, scour marks, and regional indicators of soil saturation. We have determined that no
( jurisdictional wetlands exist on the site.
Tar-Pamlico River Buffers:
The Tar-Pamlico River Buffer rules protect up to 50 feet from the edge of existing
"surface waters" (intermittent streams, perennial streams, lakes, ponds and estuaries)
found within the Tar-Pamlico River Basin that appear on either the appropriate USGS
or county soil survey map. The 50-foot buffer basically consists of two zones. The first
zone is measured 30 feet landward froth the top bank of streams and intended to
contain an undisturbed-forested area. The second zone is measured 20 feet from the
edge of the first zone and is intended to contain a vegetated buffer. We have
determined that no buffered streams exist on the site.
l Grccnshoi n Office.
Charlene Office:
236 LePhillip Corot,Suite C 3817-E Lawndale Drive
Concord,NC 28025 Greensboro,NC 27455
Phone:[phone]
f Phone: [phone] Fax*[phone]
Pax'. [phone]
( -1 (v

f
Please call or email me (wco q)sandec.com) if you should need further explanation.
Sincerely,
Walter Cole, NCLSS
Soil & Environmental Consultants, PA
` Attachments: 1) USGS site vicinity map
i 2) Hyde County Soil Survey site vicinity map
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