HomeMy WebLinkAboutSW7081208_HISTORICAL FILE_20090622STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
❑_ COMPLIANCE EVALUATION INSPECTION
DOC DATE
a2v
YYYYMMDD
North Carolina
Beverly Eaves Perdue
Governor
State Employees Credit Union
Attn: Mr. Robert S. Hall
1000 Wade Ave
Raleigh, NC 27605
Dear Mr. Hall:
�aa�s�•N 4
dl
MCDN
Division of Water Quality
Coleen H. Sullins
Director
June 22, 2009
om
Resources
Subject: Stormwater Permit No. SW7081208
SECU - Columbia, NC
High Density Commercial Wet Pond Project
Tyrrell County
Dee Freeman
Secretary
The Washington Regional Office received a complete Stormwater Management Permit Application for
the subject project on May 28, 2009. 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 2H.1000. We are forwarding Permit No. SW7081208 dated June 22, 2009,
for the construction of the subject project.
This permit shall be effective from the date of issuance until June 22, 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, P.O. Drawer
27447, Raleigh, NC 27611-7447. Unless such demands are made this permit shall be final and
binding.
If you have any questions, or need additional information concerning this matter, please contact Bill
Moore, or me at (252) 946-6481.
S cerely,
AHod�� t
9
Regional Supervisor
Surface Water Protection Section
cc: Pabst & Hilburn, PA
Wrrell County Building Inspections
ashington Regional Office
Central Files
State Stormwater Management Systems
Permit No. SV 7081208
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
STATE STORMWATER MANAGEMENT PERMIT
HIGH DENSITY DEVELOPMENT
In accordance with the provisions of Article 21 of Chapter 143, General Statutes of
North Carolina as amended, and other applicable Laws, Rules, and Regulations
PERMISSION IS HEREBY GRANTED TO
State Employees Credit Union
SECU - Columbia, NC
Tyrrell County
FOR THE
construction, operation and maintenance of a wet detention pond 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 June 22, 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 1.7 of this permit. The stormwater controls have
been designed to handle the runoff from 0.87 acres of impervious area.
3. The tract will be limited to the amount of built -upon area indicated in Section I. 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 50 feet
landward of all perennial and intermittent surface waters.
Page 2 of 7
State Stormwater Management Systems
Permit No. SV 7081208
7. The following design criteria have been provided in the wet detention pond and
must be maintained at design condition:
a.
Drainage Area, acres:
6.44 acres
b.
Total Impervious Surfaces, ftz:
37,890 sf
C.
Design Storm, inches:
1.5-inches
d.
Pond Depth, feet:
5.0 ft
e.
TSS removal efficiency:
90 %
f.
Permanent Pool Elevation, FMSI :
2.0 ft
9
Permanent Pool Surface Arei, ft :
4590 sf
h.
Permitted Storage Volume, ft
4631 cf
i.
Temporary Storage Elevation, FMSL:
2.80 ft
j.
Controlling Orifice:
1.0-inch
k.
Receiving Stream/River Basin:
UT -Scuppernong River
I.
Classification of Water Body:
SC
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.
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.
Decorative spray fountains will be allowed in the stormwater treatment system,
subject to the following criteria:
a. The fountain must draw its water from less than 2' below the permanent
pool surface.
b. Separated units, where the nozzle, pump and intake are connected by
tubing, may be used only if they draw water from the surface in the
deepest part of the pond.
Page 3 of 7
�i
State Stormwater Management Systems
Permit No. SV 7081208
c. The falling water from the fountain must be centered in the pond, away
from the shoreline.
8. 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
supporting data.
9. 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.
10. 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.
11. 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.
12. 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.
13. The permittee shall submit final site layout and grading plans for any permitted
future areas shown on the approved plans, prior to construction.
14. A copy of the approved plans and specifications shall be maintained on file by
the Permittee at all times.
III. GENERAL CONDITIONS
This permit is not transferable except after notice to and approval by the Director.
In the event of a change of ownership, or a name change, the permittee must
submit a 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.
Page 4 of 7
State Stormwater Management Systems
Permit No. SV 7081208
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
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 2006-
246, 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 June 22, 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 22 nd day of June 2009.
TH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
for
uoieen H. z>unins, uirector
Division of Water Quality
By Authority of the Environmental Management Commission
Stormwater Permit No. SV 7081208
Page 5 of 7
State Stormwater Management Systems
Permit No. SW7081208
Stormwater Permit No. SV 7081208
State Employees Credit Union
Columbia,NC
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:
Signature
Registration Number
Date
SEAL
Page 6 of 7
State Stormwater Management Systems
Permit No. SVV7081208
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.
Page 7 of 7
Z.. \
P PAA & H/L13 RN, PA
H ENGlNEERlNG B CONSULTING
June 22, 2(H)9
Mr. William J. Moore
Environmental Engineer
NCDENR - Division of Water Quality
943 Washington Square Mall
Washington, NC 27889
911 Paverstone Drive, Suite E
Raleigh, NC 27615
Office: 919.848.4399
Fax: 919.848.4395
P&H Project: 113-08
RE: Wet Detention Pond -Minor Revision- SW7081208
State Employees' Credit Union - Columbia
Dear Mr. Moore:
Per our phone conversation earlier today, the orifice device for the wet detention pond
associated with the above referenced project has been revised to a submerged orifice
outlet (enclosed Sheet CRV-3). The detail was revised based on the Typical Submerged
Orifice Outlet Configuration as shown in the NCDENR BMP Manual.
Please do not hesitate to contact me if you need additional information.
Sincerely,
PA�BST & HILBURN, PA
Patty Hilburn, PLS
President
Enclosure
•1VEGETATEDSHELF ( UM r�
ILET
(TYP) TEMPORARY `ELEV. 2D0�4
PERM ENT MO. EL".. 2.00
SHWT . 1.w —
I 4' PVC WV-200
I `SPILLWAY
SPILLWAY -AS RISER STRUCTURE
E ". 1.50 CSl
lOP K 9DWDR STORAGE _
TOP OF
ELEV. N
. RISER STRUCIUK
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INVERT
MP SHALL BE USED TO DRAW POND FOR E05P
JNTENANCE OR EMERGENCY PURPOSES r IN=
EFER 70 LANDSCAPE PLAN SHEET L7301 FOR PLANT MATERIAL el STONE BASE
UTLET PIPE SHALL WE ORING GASIQTED RCP PIPE
n WET DETENT10N POND DETAIL
f TOP OF O \^
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TYPE PLUG
4' PVC TEE
TEMPORARY POOL—& —
PERYAHMT POOL
_ I CONCRETE
1Y RISER
INV.-200I
4' PVC CAP WITH
1' HOLE DRILLiD
NTS
4' PVC STUBBED
INTO BOX
SUBMERGED ORIFICE OUTLET
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OUT-GSS
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1�+� C5103 DETAILS,_,
Architecture
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Interior �e�aRR� State Employees' Credit Union SCALE: M
tlUWI W. PDN
P. a BOX 120JT US II.y6i Columbia Office, Tvmcll County PRaEL?, 700e040
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Research Trb* Pak
North Cadna 277M Columbia, North Carolina CRV-3
BELT , OF 1
NC®ENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
February 16, 2009
State Employees Credit Union
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 fr. 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 written vegetation plan & plan details for wet pond perimeter shelf.
Wetland seed mix is not acceptable. (BMP manual, chps 6 & 10).
4. Small diameter orifices can easily clog; suggest revise orifice structure with
minimum 4-inch PVC pipe -capped and drilled to specific diameter. (See
example BMP manual, chp 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.
6. Revise application, supplements, narrative & plans as need to reflect changes.
Noah Carolina Division of Water Quality Internet w��w navaterguahty ore
943 Washington Square Mall Phone 252-946-6481 7��One
Washington, NC 27889 FAX 252-946-9215 i orth Carofina
An Equal Opportunity/Affirmative Action Employer-50% Recycledl10°/ Post Consumer Paper Naturally
Page 2 of 2
State Employees Credit Union
February 16. 2009
Page Two
The above requested information must be submitted to this office prior to March
16, 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 21-1.1000 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: bill.moore@ncmail.net.
Since/rely,,
William J. Moore
Environmental Engineer
Washington Regional Office
cc: Pabst & Hilburn, PA
Tv ell County Planning/inspections
,,,ashington Regional Office
vi J v✓\
t'1e1, `-) 0 v} `�= . DWQUSE ONLY
Date Received
Fee Paid
Permit Number
J
DEC 2 2 2008
' h
Swtwsm_(I�A
1,1n t' a ,r% State of North Carolina SV1 AC K, l" / agles
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Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This forni 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 Em looyees' 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:
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 - Columbia
5. Location of Project (street address):
US Hwy 64 (0.47 miles east of US Hwv 64 and SR 1326 intersection)
City:Columbia County: Tyrrell Zip:27925
6. Directions to project (from nearest major intersection):
US Hwy 64 (0.47 miles east of US Hwy 64 and SR 1326 intersection)
7. Latitude:35° 55' 08" N Longitude:76' 13' 57" 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:philburnQpabsthilburn.com G 34 i
I[. PERMIT INFORMATION:
1. Specify whether project is (check one): ®New ❑Renewal ❑Modification
Fonn SWJJ-101 Version09.25.08 Page 1 of4
2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the
existing permit
and its issue date (if
3. Specify the type of
❑Low Densi gh Density ❑Redevelop mit ❑Universal SMP ❑Other
4. Additional Proj menu (check applicable blanks; information on required state permits can be
obtained by contacting the Customer Service Center at 1-877-623-6748):
❑LAMA 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 approved plans
prepared by Pabst & Hilburn, PA. Stormwater from the wet ponds will be discharged into an existing
storm drainage system located along US Hwy 64 and into an existing ditch located in the rear of the site.
2. Stormwater runoff from this project drains to the Pasquotank River basin.
3. Total Property Area: 6.44 acres 4. Total Coastal Wetlands Area: N/A acres
5. Total Property Area (3) - Total Coastal Wetlands Area (4) = Total Project Area**: 6.44 acres
6. (Total Impervious Area / Total Project Area) X 100 = Project Built Upon Area (BUA): 15.1 %
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, complete the table with one drainage area for each engineered stormwater device.
Basin Information
Drainage Area 1
Drainage Area 2
Receiving Stream Name
Scuppernong River
Scuppernong River
Stream Class & Index No
SC / 30-14-4-(9)
SC / 30-14-4-(9)
Total Drainage Area (so
43,779
18,677
On -site Drainage Area (so
43,779
18,677
Off -site Drainage Area (so
0
0
Existing Impervious* Area (so
0
0
Proposed Impervious*Area (so
23,166
14,411
% Impervious* Area (total)
52.9
77.2
Impervious* Surface Area
Drainage Area 1
Drainage Area 2
On -site Buildings (so
4,243
On -site Streets (so
On -site Parking (so
15,468
13,443
On -site Sidewalks (so
1,875
968
Other on -site (so
1,580
Off -site (so
Total (so:
23,166
14,411
Impervious area is defined as the built upon area including, but not limited to, buildings, rends, parking areas,
sideroalks, gravel areas, etc.
Form SWU-101 Version 09.25.08 Paee 2 of
**Total project area shall be calculated to exclude Coastal Wetlands froiu 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? Areas taken from CAD
Projects in Union County: Contact the DWQ Central Office 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/bmo 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 DRPC4
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 htto:Hl12o.enr.state.nc.LIS/Su/bap forms.htm.
Form SW401-Low Density
Form SW401-Curb Outlet System
Form SW401-Off-Site System
Form SW401-Wet Detention Basin
Form SW401-Infiltration Basin
Form SW401-Infiltration Trench
Form SW401-BioretenHon Cell
Form SW401-Level Spreader
Form SW401-Wetland
Form SW401-Grassed Swale
Form SW401-Sand Filter
Form SW401-Permeable Pavement
Form SW401-Cistern
Low Density Supplement
Curb Outlet System Supplement
Off -Site System Supplement
Wet Detention Basin Supplement
Infiltration Basin Supplement
Underground Infiltration Trench Supplement
BioretenHon Cell Supplement
Level Spreader/Filter Strip/ Restored Riparian Buffer Supplement
Constructed Wetland Supplement
Grassed Swale Supplement
Sand Filter Supplement
Permeable Pavement Supplement
Cistern Supplement
Fomr SWU-101 Version 09.25.08 Page 3 of 4
Vl. 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.nc.us/su/msi mans.htm)
1. Please indicate that you have provided the following required information by initialing in the space provided
next to each item.
I ' 'GIs,
• 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) ,I
payable to NCDENR lzTt —
• Calculations & detailed narrative description of stormwater treatment/management
• Copy of any applicable soils report (t aC-U'_c>e0 L. Ce+, C.a
• Two copies of plans and specifications (sealed, signed & dated), including: G
- 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
Email:philburn@pabsthilburn.com
VIII. APPLICANT'S CERTIFICATION
Fax: (919 ) 848-4395
I, (print or type tame 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 record d, and that the proposed project complies with the requirements of 15A
NCAC 2H .1000. �\ n
Date: I z1a01(9V
Form SW U-101 Version 09.25.08 Page 4 of 4
&P�ABSTa�ILBUR�
PA
ENGCONSUING
LETTER OF TRANSMITTAL
To: NCDENR
Division of Water Quality
943 Washington Square Mall
Washington, NC 27889
Re: SECU — Columbia
Stormwater Permit Submittal
1 am sending you the following item(s):
911 Paverstone Drive, Ste. E
Raleigh, NC 27615
Office: 919.848.4399
Fax: 919.948.4395
Date: 12/19/08
Job No.: 113-08
COPIES
DATE
NO.
DESCRIPTION
2
12/05/08
Plans
2
12/05/08
Design Narrative and Supporting Calculations (Includes Soil Report)
2
12/10/08
Stonnwater Permit Application (1-Original, 1-Copy)
2
12/10/08
Wet Pond Supplement Forms (1 - Pond #1, 1 - Pond #2)
1
12/10/08
Permit Application Permit Fee - $505.00 (Check #23619)
These are transmitted as checked below:
❑
As requested
®
For approval
®
For review and comment
DEC k 2 Z068
❑ For your use
❑ For Signatures
❑ For Submittal
Re am�ri(s
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. c[
Copy to: File Signed: f 1---
Patt ilbum, PLS
I
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�� SW%S)a08
FINANCIAL RESPONSIBILITY/OWNERSHIP FORM
SEDIMENTATION POLLUTION CONTROL ACT
No person may initiate any land -disturbing activity on one or more acres as covered by the Act before this
form and an acceptable erosion and sedimentation control plan have been completed and approved by the
Land Quality Section, N.C. Department of Environment and Natural Resources. (Please type or print and, if
the question is not applicable or the e-mail and/or fax information unavailable, place N/A in the blank.)_
Part A. "tt'_' �t4 t rr,
1. Project Name State Empolvees' Credit Union — Columbia DEC 2 9 2008
2. Location of land -disturbing activity: County T rrel� I City or Township Columbia"ar,r ; t11t 6' rr
Highway/Street US Hwv 64 Latitude 35.9167 Longitude 76.2325
3. Approximate date land -disturbing activity will commence: January 1, 2009
4. Purpose of development (residential, commercial, industrial, institutional, etc.): Commercial
5. Total acreage disturbed or uncovered (including off -site borrow and waste areas): 2.48 Ac.
6. Amount of fee enclosed: $ 195.00 . The application fee of $65.00 per acre (rounded
up to the next acre) is assessed without a ceiling amount (Example: a 9-acre application fee is $585).
7. Has an erosion and sediment control plan been filed? Yes No Enclosed X
8. Person to contact should erosion and sediment control issues arise during land -disturbing activity:
Name Patty E. Hilburn
Telephone (919) 848-4399 Cell #
E-mail Address philburn0i)absthilburn com
Fax # (919) 848-4395
9. Landowner(s) of Record (attach accompanied page to list additional owners):
State Employees' Credit Union
Name Telephone Fax Number
P.O. Box 27665
Current Mailing Address Current Street Address
Raleigh NC 27611
City State Zip City State Zip
10. Deed Book No. 218 Page No. 164 Provide a
Part B.
Person(s) or firm(s) who are financially responsible for the land- stur' inng activity20(Prro
comprehensive list of all responsible parties on an attached sheet):
State Employees' Credit Union LAND QUALITY SECTIONI REGIONAL Of
Name = --;I ,,....__ _
1000 Wade Avenue
Current Mailing Address Current Street Address
Raleigh NC 27605
City State Zip City State Zip
Telephone 919 839-5000 Fax Number
2. (a) If the Financially Responsible Party is not a resident of North Carolina, give name and street address
of the designated North Carolina Agent:
WY,
Name E-mail Address
Current Mailing Address Current Street Address
City,,' State Zip City
State Zip
Telephone Fax Number
(b) If the Financially Responsible Party is a Partnership or other person engaging in business under an
assumed name, attach a copy of the Certificate of Assumed Name. If the Financially Responsible
Party is a Corporation, give name and street address of the Registered Agent:
E-mail Address
Name of Registered Agent
Current Mailing Address
City
Current Street Address
Zip City
Telephone Fax Number
State
The above information is true and correct to the best of my knowledge and belief and was provided
by me under oath (This form must be signed by the Financially Responsible Person if an individual
or his attorney -in -fact, or if not an individual, by an officer, director, partner, or registered agent with
the authority to execute instruments for the Financially Responsible Person). I agree to provide
corrected information should there be any change in the information provided herein.
Robert S. Hall Sr. Exec, Vice President
Type or print name 1 Title or Authority
SignaWre l Date
17 Av-\n JA) ( O V 2 V- a Notary Public of the County of vk K 2
State of North Carolina, hereby certify that ::� - 5, ka l � appeared
personally before me this day and being duly sworn acknowledged that the above form was
executed by him.
Witness my hand and notarial seal, this day of PJOII e- M lv)e-r , 20 D
Ar
Seal
oa�=`.,
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N�rYZu•4I� tRV1vv eG.Vet�
My commission expires /J e �j, I q , a01 a
A. 23619
OBRIENATKINS 23619
POST OFFICE BOX 12037 WACHOVIA BANK, N.A.
RESEARCH TRIANGLE PARK, NO 27709 66-21-530
0
DATE AMOUNT e
PAY THE SUM OF FIVE HUNDRED FIVE DOLLARS 00/100 ONLY 12/10/2008 $505.00
Y
TO THE
ORDER NC DEPT OF ENVIR & NATURAL s
OF
RESOURCES O•B N/ATKINS ASSOCIATES, P.A.
r
cnc tt waanneani
Total Suspended, Volatile and Fixed Solids
Standard Methods 18th ed 2540 D and Standard Methods 14th ed 208 E
Lab # to
Page of
QCS
Balance
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initial:
Micro ID
Information
Set up
Read back
TRUE VALUE m /L
Sartorius
Date
Date
FOUND m /L
Analytical
Balance
date:
Analyst
Analyst
RANGE m /L
Checked by: date:
Checked by: date:.
#20401645
definitions:
Ar= weight of deed residue+ fiber (mg)
Ai= re-dried(check)of weight of Ar (mg)
Duplicate Information
Abbreviation KEY
A=Averaged Value S= Total Suspended
C OC =Volatile& Fixed T=Total Residue
COChain of Custody
Sample:
Sam le:
Duplicate:
Du licate:
%RPD:
%Rpp
tr = initial weight of filter(mg)
Orvinq Time Information
1, re-ignited(check) of weight of 11
1st drying time
Tem °C
2nd drying time
Tem . °C
1 st ignition time
Temp . °C
2nd ignition time
Temp. °C
81=weight after ignition(mg)
Bs=re-ignited(check) of weight of B,
Time in
Time out
Time In
Time out
Time in
Time out
Time in
Time out
NOTE: Use � for calculation if within 4% or 0.0005
g of _1
Lab #
K
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Filter
#
Sample
Vol (ml)
Filter
weight (mg)
(Ir)
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weight (mg)
(At)
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weight (mg)
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comments
DWQ USE ONLY
Date Received
Fee Paid
Permit Number
v
V �—
S
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
r F" ram a
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This form may be photocopied for nse as an original MAR 1 3 2009
1. GENERAL INFORMATION
1. Applicants name (specify the name of the corporation, individual, etc. who owns the project): '
State Employees' 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 - Columbia
5. Location of Project (street address):
US Hwy 64 (0.47 miles east of US Hwy 64 and SR 1326 intersection)
City:Columbia County: Tyrrell Zip:27925
6. Directions to project (from nearest major intersection):
US Hwy 64 (0.47 miles east of US Hwy 64 and SR 1326 intersection)
7. Latitude:35° 55' 08" N Longitude:76° 13'
8. Contact person who can answer questions about the project:
Name:Pabst & Hilburn, PA (Patty E. Hilburn) Telep
Email:philbtim@pabsthilbum.com
IL PERMIT INFORMATION:
(919 ) 848-4399
�41�� 89f's-43�s` f
1. Specify whether project is (check one): ®New ❑Renewal ❑Modification
2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the
existing permit number 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
Fonn SWU-101 Version 09.25.08 Page I of
obtained by contacting the Customer Service Center at 1-877-623-6748):
❑LAMA 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 a storm drainage system to the wet detention pond as shown on
approved plans prepared by Pabst & Hilburn, PA. Stormwater will be discharged from the wet pond into an
existing farm ditch located in the rear of the site.
2. Stormwater runoff from this project drains to the Pasquotank River basin.
3. Total Property Area: 6.44 acres 1 4. Total Coastal Wetlands Area: N/A acres
5. Total Property Area (3) - Total Coastal Wetlands Area (4) = Total Project Area**: 6.44 acres
6. (Total Impervious Area / Total Project Area) X 100 = Project Built Upon Area (BUA): 15.1 %
7. How many drainage areas does the project have? 2 , B 716. 44- ;� J 4-'
S. 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 rovided in the same format as below.
For high density projects, complete the table with one drainage area for each engineered stormwater device.
Basin Information
Drainage Area 1
Drainage Area 2
Receiving Stream Name
Scuppernong River
Scuppemong River
Stream Class & Index No.
SC / 30-14-4-(9)
Total Drainage Area (sf)
50,803 1 `%QL
On -site Drainage Area (sf)
50,803
Off -site Drainage Area (sf)
0
Existing Impervious* Area (sf)
0
Proposed Impervious*Area (sf)
37,890
% Impervious* Area (total)
75%
Impervious* Surface Area
Drainage Area 1
Drainage Area 2
On -site Buildings (sf)
4,243
On -site Streets (sf)
On -site Parking (sf)
28,053
On -site Sidewalks (sf)
3,008
Other on -site (sf)
2,586
Off -site (sf)
Total (sf):
j 37,890 , 8 'J a
,
Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
sidetualks, gravel areas, etc.
**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? Areas taken from CAD
Projects in Union County: Contact the DWQ Central O%fice slaff to check to see i%you project is located
within a Threatened & Endangered Species watershed that may be subject to more stringent svornwater
requirements.
Form SWU-101 Version 09.25.08 Page 2 ot4
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/bml2 forms.htm.
Form SW401-Low Density
Form SW401-Curb Outlet System
Form SW401-Off-Site System
Form SW401-Wet Detention Basin
Form SW401-Infiltration Basin
Form SW401-Infiltration Trench
Form SW401-Bioretention Cell
Form SW401-Level Spreader
Form SW401-Wetland
Form SW401-Grassed Swale
Form SW401-Sand Filter
Form SW401-Permeable Pavement
Form SW401-Cistern
Low Density Supplement
Curb Outlet System Supplement
Off -Site System Supplement
Wet Detention Basin Supplement
Infiltration Basin Supplement
Underground Infiltration Trench Supplement
Bioretention Cell Supplement
Level Spreader/Filter Strip/Restored Riparian Buffer Supplement
Constructed Wetland Supplement
Grassed Swale Supplement
Sand Filter Supplement
Permeable Pavement Supplement
Cistern Supplement
FormSWU-101 Version09.25.08 Pace 3of4
V1. 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 compplete 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.nc.us/su/msi_maos.htm)
Please indicate that you have provided the following required information by initialing in the space provided
next to each item.
Initials
• Original and one copy of the Stormwater Management Permit Application Form
• 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)
VIL 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
Email:philbum@pabsthilbtirn.com
VIII. APPLICANT'S CERTIFICATION
Fax: (919 ) 848-4395
I, (print or type name of person listed in General Information, item 2) Robert S. Hall
certify that tine 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 recgrl.ed,
NCAC 2H .1000. , I nd that the proposed project complies with the requirements of 15A
Signa
Date: 3 /
Fonn SWU-101 Vernon 09.25 08 Page 4 of 4
PABST � HILBURIV, P,9
I..I ENGINEERING 8 CONSULTING
March 11, 2009
Mr. William J. Moore
Environmental Engineer
NCDENR - Division of Water Quality
943 Washington Square Mall
Washington, NC 27889
MAR 1 3 2009
911 Paverstone Drive, Suite E
Raleigh, NC 27615
Office: 919.848.4399
Fax: 919.848.4395
P&H Project: 113-08
RE: Responses to Stormwater Review Comments - SW7081208
State Employees' Credit Union - Columbia
Dear Mr. Moore:
Please find below responses to stormwater review comments dated February 16, 2009.
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).
P&H Response: As requested, the wet pond design has been revised to include an
average depth of 3 feet or more, which does not include the 1 foot of sediment
depth.
2. Soils report indicates the seasonable 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 -4.0 ft.
Explain/justify design elevations.
P&H Response: The SHWT in the rear of the site is approximately 24-inches below
the existing ground elevation per the soil evaluation prepared by S&EC on
September 4, 2009, which would be at an approximate elevation of 0.50 ft. The
pond's permanent pool elevation was set at 2 ft due to the outlet invert
constraint; therefore, a geosynthetic liner will be installed to maintain the
permanent pool at 2 ft. Please find the enclosed Storm Water Pond report
prepared by GeoTechnologies, dated March 4, 2009.
3. Provide written vegetation plan & plan details for wet pond perimeter shelf.
Wetland seen mix is not acceptable. (BMP Manual, chapters 6 & 10).
P&H Response: Vegetation for pond perimeter shelf has been revised per chapters
6 & 10 of the BMP Manual. See Sheet L1301 for revision.
4. Small diameter orifices can easily clog; suggest revise orifice structure with
minimum 4-inch PVC pipe -capped and drilled to specific diameter. (See example
BMP Manual, chapter 10).
P&H Response: Orifice structure has been revised to a 4-inch PVC pipe -capped and
drilled to 1-inch diameter as suggested. See Sheet C5103 for reivision.
5. The proposed wet ponds are relatively small; suggest eliminating diversion
berms to enhance sediment storage. Also, top of forebay berms should be 6-
inches below design permanent pool elevation.
P&H Response: Pond #2 shown on original submittal has been removed and storm
drainage added to direct runoff to the pond in the rear of the site. The diversion
berms have been removed and forebay berm elevation is now 6-inches below the
permanent pool elevation. See Sheet C1201 and C5103 for revision.
6. Revised application, supplements, narrative & plans as needed to reflect
changes.
P&H Response: All of the above have been revised to reflect changes as
requested.
Please do not hesitate to contact me if you need additional information in order to
expedite this process.
Sincerely,
PABST & HIL�BU1RN, PA
0
Patty E. Hilburn, PLS
Principal
Enclosure
&PA BST a HILBURN, PA
ENGlIJEERlNG a CONsuL , G
LETTER OF TRANSMITTAL
To: Bill Moore
NCDENR - Division of Water Quality
943 Washington Square Mall
Washington, NC 27889
Re: SECU — Columbia
Stormwater Permit Submittal
I am sending you the following item(s):
MAR 1 3 2009
911 Paverstone Drive, Ste. E
Raleigh, NC 27615
Office: 919.848.4399
Fax: 919.848.4395
Date: 3/12/09
Job No.: 113-08
COPIES
DATE
NO.
DESCRIPTION
2
3/04/09
Revised Plans
2
3/05/09
Revised Design Narrative and Supporting Calculations
2
3/06/09
Revised Stormwater Permit Application (1-Original, 1-Copy)
2
3/06/09
Revised Wet Pond Supplement (1-Original, 1-Copy)
1
3/04/09
Storm Water Pond Report by GeoTechnologies
1
3/11/09
Written Responses to Review Comments
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 Signeci 6 ;� 5 '__1
r P E. Hilburn, PIS
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&P�ABST& HILBURN, PA
ENGINEERING & CONSULTING
LETTER OF TRANSMITTAL
To: Bill Moore
NCDENR - Division of Water Quality
943 Washington Square Mall
Washington NC 27889
Re: SECU — Columbia
Stormwater Permit Submittal
I am sending you the following item(s):
MAY 2 8 2009
�?C
911 Paverstone Drive, Ste. E
Raleigh, NC 27615
Office: 919.948.4399
Fax: 919.948.4395
Date: 5/27/09
Job No.: 113-08
COPIES DATE NO. DESCRIPTION
2 5/27/09 Revised Plans
2 5/26/09 Revised Wet Detention Supplement
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 per our phone conversation last week. Do not hesitate to
call if you have any questions or need additional information. Thank you.
Copy to: File Signed: a�G
Patty E. Hilburn, PLS
�e3�CS �Yt r.etcn'.rtzi ,,�
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29n 0 pnOvil aril Lo; I.Sm ,r a t
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109
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\ Geotechnical and Construction Materials Testing Services
March 4, 2009
Julie McLaurlin
O'BRIEN/ATKINS & ASSOCIATES
P.O. Box 12037
RTP, NC 27709
Re: Storm Water Pond
SECU @ Hwy-64
Columbia, North Carolina
GeoTechnologies Project No. 1-08-0403-EA
Dear Ms. McLaurlin:
MAR 1 3 2009
4 ..r r? r1LY`.till
GeoTechnologies, Inc. completed a subsurface investigation for the referenced site in 2008.
Subsequently, we were requested to assist the project civil engineer with geotechnical design and construction
issues related to the storm water pond which will be located at the back of the property. Specifically, we were
requested to assist with specifying a geosynthetic liner for the interior of the pond, to provide construction
dewatering recommendations, and to provide recommendations for liner protection during periodic sediment
removal from the bottom of the pond. This letter presents our recommendations regarding these issues.
Geosynthetic Liner. We understand permanent pool must be maintained at El +2. To maintain
permanent pool at El +2, a synthetic liner will have to be installed below the entire below the entire basin area.
Even with a fully lined basin, water levels will drop during periods of drought due to evaporation unless a make
up well is installed.
A number of suitable liner products are available for this application; however, it is our recommendation
that a 30 mil PVC geomembrane be used. Environmental Protection, Inc. (EPI) in Mancelona, Michigan (1-800-
OK-LINER) can manufacture and package the panels per the pond requirements, and then ship the liner to the
site. A specification sheet for this liner is attached to this letter. The advantage of PVC is that it can be field
welded by the contractor without special equipment and without a specialty installer. Alternate liners may also
be considered though if the contractor wants to submit an alternate.
Drainage and Maintenance. Unbalanced hydrostatic forces below or behind the liner could result in its
flotation or movement. Seepage losses will be minimized through the proper installation of the recommended
liner, and therefore, water levels should only have the potential to become significantly depressed during
extended periods of dry weather, or if the pond has to be lowered for maintenance.
To facilitate pond recharge during dry periods, and/or to eliminate unbalanced hydrostatic forces during
drawdown, we recommend incorporating recharge pipes as shown in attachments to this letter. A typical
recharge pipe detail has been included; however, the exact details and the exact location for the recharge pipe
should be established in the field at the time of construction based on observations made in the field. The intent
3200 Wellington Court, Suite 108 • Raleigh, North Carolina 27615 • Phone 919-954-1514 • Fax 919-954-1428 • www.geotechpa.com
O'Brien/Atkins & Assoc.
Re: SECU/Columbia
March 4, 2009
Page: 2
will be to extend a wet well down into clean sands which can act as a recharge source. The contractor will have
to utilize pipe boots to prevent seepage around the pipes after they have been installed.
The general area grade above the primary wet detention pond and forebays is at El +1 to El +2 which
is at or slightly above the water level which likely will exist during various times of the year. Accordingly, we
suggest that any cleaning of the ponds be conducted in the wet without dewatering the forebays or the main
detention pond. This can be accomplished utilizing a trackhoe or backhoe with a smooth bucket working from
the top of the pond during drier periods of the year. By planning for maintenance in this way, it will not be
necessary to install a permanent underdrain system around the facility which would require reactivation during
periods of maintenance. However, the maintenance directions for this facility should make it clear that
dewatering of the interior of the ponds is not recommended.
During very dry years when the water table drops as a result of drought conditions, we would anticipate
that water levels will fall sufficiently such that clean -out of the forebays could be accomplished in the dry and
that access back to the primary wet detention pond could be obtained with only very minor difficulty. Placement
of recharge pipes will allow the pond and forebay to be recharged with standpipes through the artesian condition
that will be created if water levels outside of the pond (static groundwater) exceed those on the interior. An EPI
detail (pipe boot installation) is included in this report for installing standpipes through the liner. A flap valve
should also be included on the top of the standpipe to prevent backflow. We recommend that pipe inverts be set
at the elevations on the attached drawing.
Dewatering Considerations. The test borings suggest that groundwater is likely to be encountered at
about El +1 to El 0. This implies that the contractor may be able to control groundwater with deeper perimeter
ditches although this can only be determined by attempting the operation at the time of construction. One
possible construction sequence would involve first installing a deep perimeter ditch around the exterior of the
area which will have to receive a synthetic liner. A pump would be installed in the ditch to pump and hold water
levels down drawing water levels below El 0 on the interior of the area to be lined. The contractor would then
install an additional dewatering sump and/or install well points in the area of the proposed deep detention basin.
Since clean sands were encountered at depth in some of the borings, the contractor may have to employ well
points to drop the water levels to El -5 to -6 so that he can construct the bottom of the wet detention pond.
Once the water level has been dropped below the bottom of the pond, the contractor should then shape
the bottom and begin installing the synthetic liner. We would anticipate that he will have to install the liner in
the base of the wet detention basin first, complete construction of that basin, fill it with water, turn off the deeper
dewatering system, and continue pumping from the perimeter to then complete the installation.
The contractor should be responsible for all means and methods with regard to installation of the wet
detention pond, and the possible sequence shown in a figure attached with this letter is for general information
purposes only. We will be happy to assist the contractor during the construction process if he needs assistance in
identifying the next approach to take in the dewatering operation or construction operation. It is very important
that the deepest portion of this pond be constructed, protected, and then filled with water before turning the
system off to prevent the liner from floating.
Liner Protection During Maintenance Sediment which accumulates at the bottom of the pond will
occasionally need to be removed. Damage to the liner can occur during cleaning, and it is our recommendation
that the liner along the bottom and portions of the side slopes be protected. We recommend that the protection
consist of either 12 inches of a soil -cement mixture (5% cement by weight added to on -site approved granular
www.geotechpa.com
O'Brien/Atkins & Assoc.
Re: SECU/Columbia
March 4, 2009
Page: 3
soils), or solid 4 inch thick Armorloc blocks (1-800-305-0523) placed over either 8 inches of approved on -site
granular soils or a 14 ounce nonwoven geotextile fabric. The protection should extend along the bottom of the
pond up the side slopes to at least El +1.
SUMMARY
In summary, the requirements for the wet detention basin at Columbia will necessitate use of a synthetic
liner to maintain permanent pool at about El +2. Construction of the pond will require good technique on the
part of the contractor to control groundwater until the pond is constructed and will require attention to detail
during installation of liners, recharge pipes, soil cover, and a protective layer in the base of all areas which will
require future cleaning. The details attached with this letter are intended as a general guide to provide the
contractors with an indication of the scope of the issues which will have to be addressed during the construction
of this pond.
GeoTechnologies, Inc. appreciates the opportunity to be of service on this phase of the project. Please
contact us if you have any questions concerning this letter or if we may be of additional service on this or other
projects.
Sincerely,
GeoTechnologies, Inc.
Edward B. Hearn, P.E.
NC Registration No. 9520
EBWpr-dli/lam
Attachments
1080403ca-4.doc
www.gootechpa.com
EXISTING GROUNDWATER AND PERMANENT POOL
Existing Grou
Note: Ground water elevation will vary seasonally
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A POSSIBLE CONSTRUCTION SEQUENCE
Note: The contractor is responsible for all means and methods for Installing the
wet detention pond. This possible sequence has been prepared to alert the
contractor to the fact that groundwater control, sequencing, and filling
depressed areas before turning off temporary water control measures
will be critical to proper long term performance of the pond. (/),
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TYPICAL DETAIL FOR RECHARGE PIPES
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Columbia SECU
Columbia, North Carolina
le
JOB No: 9-08-0403-EA
FIGURE No: 1
Depth (Feet) GENERALIZED SUBSURFACE PROFILE
LEGEND
B-1 B- 2 B- 3 B- 4 B- 5 B- 6 B- 7 B- 8 B- 9 B-10 B-11 Topsoil
0 gl_,
4 8 8 6 6 7 78 3 �5 �7 6 ® Low Plasticity Silt
��77 4
5 3 1(3"- 5Q 8� 9� 77 14 76_�
Silty Sand
4 4 ®
4 — WO 7 �..1 10 7 4 ® Low Plasticity Clay
10 g 3 ;;.. 7 4 ��}; 5 8 6 �f Poorly -graded Sand
® Low Plasticity Silt to Clay
15 7 11 5 6 1. 5 5 9
• ® Clayey Sand
20 7 8 15 12 11 16 12 organic Silt or Clay
Fine to Coarse §SAND
25 6 "' _r 7 Low Plasticity Silt to Silty Sand
® Interlayered Sand and Clay
30 14 11
Poorly -graded Sand with Silt
c�7 8 Standard Penetration Resistance
35 13 16
•'�+ y Groundwater at Time of Boring
40 24 • 8 Groundwater after Time of Boring
tl 45
50 5 27
"
55
Columbia SECU
Columbia, North Carolina
SCALE: As Shown
JOB No:1-08-0403-EA
FIGURE No:2
Liner Company
TYPICAL
APPLICATIONS:
Reservoirs
Canals
Sewage Lagoons
Landfill Closures
Soil Remediation
Farm Ponds
Water Features
1.
Irrigation Ponds
Golf Course Ponds
Heap Leach Pads
Industrial Waste
Ponds
Tailings Ponds
30 rail PVC Geornern rave
Specifications
PVC liners fabricated by EPI
Thickness t 5%
ASTM D-5199 .030"
are a single -ply construction with
Specific Gravity (min)
ASTM D-792 1.20
Polyvinyl Chloride as the
principle polymer. Only first
Tensile (lb/in-width, min)
ASTM D-882 73
quality virgin resins are used
and all materials meet or exceed
Elongation at Break (% min)
ASTM D-882 380
the requirements of ASTM D-
7176 Standard Specification for
Modulus (lb/in-width, min)
ASTM D-882 30
PVC geomembranes used In
buried applications.
Tear Resistance (lb/In, min)
ASTM D-1004 8
Resistance to Soil Burial
ASTM G-160
EPI utilizes statistical
(% change, max)
process control (SPC) to ensure
1. Breaking Factor
5
the integrity of each panel
2. Elongation At Break
20
produced. Samples from actual
3. Modulus at 100% Elongation
20
factory seams are removed
during the welding process for a
Impact Cold Crack ('C)
ASTM D-1790 -29
rigorous, proven testing
Dimensional Stability
ASTM D-1204
procedure that assures you of
(% change, max)
(212°F/15 min.) 3
the highest quality factory -
fabricated PVC geomembranes
Water Extraction (%,max)
ASTM D-1239 0.15
available.
Volatile Loss (%, max)
ASTM D-1203(A) 0.70
Hydrostatic Resistance
ASTM D-751(A) 100
PVC Liners are fabricated by
(psi, min)
EPI in panels, accordion -folded
Plasticizer Min Ave Melee Wt
ASTM 2124 400
in both directions, and packaged
for shipment to your site for
Factory Fabricated Seams:
quick, easy installation to save
Peel Strength (Ibs/in, min)
ASTM D-882 15
Shear Strength (lbs/In, min)
ASTM D-882 58.4
These data are based on tests believed to be reliable. However, these are laboratory tests that may not
simulate actual use conditions. They are provided for yourinformational purposes only. No warranty,
express or implied, including any other further warranty of illness for a particular purpose or
merchantability, is made by this promotional literature
�0]'f',St'1'f'll7i7e'a1(?r)'aoUJI'('rSlor)1r'1owgo `%lllo .
Visit our Internet web site at
wrw►w.geomembrane.com
PROTECTIONi INC.
Pipe Boot Installation
Step 1:
Prepare the subgrade around
the area of the pipe. The sub -
grade must be smooth, uniform,
and free of any protrusions.
Step 2:
Clean the surface of the liner
around the penetration where the
boot will be welded in place.
Wipe away any dirt or dust
particles. The surfaces of the
liner, boot, and the pipe must be
completely clean and dry.
Step 3:
Slide the boot sleeve on the
pipe, making sure the boot is
aligned and all surfaces are
smooth.
It may be necessary to trim the
excess tapered portion of the boot
sleeve.
Step 4:
Weld the boot apron to the liner
using EPI provided adhesive.
Apply the adhesive to the liner and
the boot apron. Let the adhesive
setup for several seconds before
pressing the boot apron and the
liner together using a roller. Make
sure to smooth out any bubbles or
wrinkles.
Step 5:
Seal the boot sleeve to the pipe
using the stainless steel hose
clamp. The clamp around the pipe
will form a watertight seal to the
pipe.
Pleat valilt
1'trserr'trh r�'rrl�>t' !'r'srJtt»'Ps ��)T��IIrrFF.* � �r�rrrli��tts
For technical assistance, call Elul toll free
600-655-4637
ARMORTEC
Eroa(on Conrolt
- ?
�� S� vF'.a..c..bs 4 �% 14..hnent.� `� V' l* .y«k � ♦ , r. s
faz.'h,,,r rrienn R Ph:.nnvre'P afaek ietre s+e:r.'cSe73 �o`rm�hal.ria eroson.r.'f�hhi-oModerr�L�ito�d.,l �s Y`f`,,. R, "r"rM'Solutions roc
G
�. not feasit
areas.A
ject to
able ins
tr ciliatilt
vegetati
property.
s _ proper pro
ply ��•,, .
commercial
'S silicalions which
open - channeFflow conditions.. For neariy M years. Arm
sites from ditches and settling basins to channel lining or
•
All around Interlocking effect
One basic block makes up, complete protection
system, no smaller blocks required to complete
Interlock
Strong and durable -
Fleiiihle, conforms to ground contours
Q Relieves hydrostatic pressure
' jb:Safeiurfacefor pedestrians, vehicles andboatsl
outer and road Sol
fd laboi or,heovy s
rEvery, Atmorioc block9s not only secured by four blocks In ,I
,the neighboring sours, but by six surrounding blocks, as
shown here. ,
Sol particles trapped between the Joints of the Atmorloc
block act as dry giout. binding the blocks Into a continuous
mahiess.
Open cells and joints between Armortoc blocks provide a
perfect onvironment,for the evoblishment of vegetation.
The roots of gross and small' shrubsprovide o permanent
anchor for the Installation whit beautifying the landscopa.