SW8051217_HISTORICAL FILE_20080822

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW8 01)
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
IR HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
20 o 5 o 8 22
YYYYMMDD

.� OF WAlFj9 Michael F. Easley, Governor
�O (. William G. Ross Jr., Secretary
rNorth Carolina Department of Environment and Natural Resources
� 1.
Q Coleen H. Sullins Director
Division of Water Quality
August 22, 2008
Carmen Gintoli, Director Facilities
New Hanover County Schools
6410 Carolina Beach Road
Wilmington, NC 28412
Subject: Stormwater Permit No. SW8 051217 Modification
Ogden Elementary School
High Density Project
New Hanover County
Dear Mr. Gintoli:
The Wilmington Regional Office received a complete Stormwater Management Permit
Application for Ogden Elementary School on August 20, 2008. Staff review of the plans and
specifications has determined that the project, as proposed, will comply with the Stormwater
Regulations set forth in Title 15A NCAC 2H.1000. We are forwarding Permit No. SW8 051217
Modification dated August 22, 2008, for the construction of the subject project.
This permit shall be effective from the date of issuance until February 13, 2016, and shall be
subject to the conditions and limitations as specified therein. Please pay special attention to
the Operation and Maintenance requirements in this permit. Failure to establish an adequate
system for operation and maintenance of the stormwater management system will result in
future compliance problems.
If any parts, requirements, or limitations contained in this permit are unacceptable, you have
the right to request an adjudicatory hearing upon written request within 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 Rhonda Hall, or me at [phone].
Si erely,
ZaA�Z/Ie�
Edward Beck
Regional Supervisor
Surface Water Protection Section
ENB/rbh: S:\WOS\STORMWAT\PERMIT\051217MOD.aug08
cc: Renee Scott, CLH design, p.a.
New Hanover County Building Inspections
City of Wilmington Development Services
Beth E. Wetherill, New Hanover County Engineering
Rhonda Hall
Wilmington Regional Office
Central Files
NollhCarolina
Al tura/!y
North Carolina Division of Water Quality 127 Cardinal Drive Extension Wilmington, NC 28405 Phone [phone]
Wilmington Regional Office Internet: ,w .nc.aterquality.orC Fax [phone]
An Equal Opportunity/Affirmative Action Employer— 50 % Recycled/10 % Post Consumer Paper
Customer Service
1-877-623-6748

aw<�
State Stormwater Management Systems
Permit No. SW8 051217
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
Carmen Gintoli & New Hanover County Schools
Ogden Elementary School
3637 Middle Sound Loop Road, Wilmington, New Hanover County
FOR THE
construction, operation and maintenance of three infiltration basins in compliance with
the provisions of 15A NCAC 2H .1000 (hereafter referred to as the "stormwater rules')
and the approved stormwater management plans and specifications and other
supporting data as attached and on file with and approved by the Division of Water
Quality and considered a part of this permit.
This permit shall be effective from the date of issuance until February 13, 2016, and
shall be subject to the following specified conditions and limitations:
I. DESIGN STANDARDS
This permit is effective only with respect to the nature and volume of stormwater
described in the application and other supporting data.
2. This stormwater system has been approved for the management of stormwater
runoff as described in Section 1.6 on page 3 of this permit. The stormwater
controls Ipbeled B1,2B2 and C have been designed to handle the runoff from
62,320 ft , 54,869 ft , and 51,030 ft , respectively, of impervious area. Each
infiltration basin must be operated with a 50' vegetated filter.
3. The overall tract and each individual drainage area will be limited to the amount
of built -upon area indicated on page 3 of this permit, and per approved plans.
This permit does not make provision for any future built -upon area.
4. All stormwater collection and treatment systems must be located in either
dedicated common areas or recorded easements. The final plats for the project
will be recorded showing all such required easements, in accordance with the
approved plans.
5. The runoff from all built -upon area within the permitted drainage area of this
project must be directed into the permitted stormwater control system.
Page 2 of 7

State Stormwater Management Systems
Permit No.
SW8 051217
6. The
following design criteria have been provided in the infiltration
basin and must
be maintained at design condition:
Basin Number:
131
B2
C
a.
Drainage Area, acres:
2.24
3.17
1.59
Onsite, ft2:
97,574
138,085
69,360
Offsite, ft2:
0
0
0
b.
Total Impervious Surfaces, ft2:
62,320
54,869
51,030
C.
Design Storm, inches:
1.5
1.5
1.5
d.
Basin Depth, feet:
2.0
2.0
2.0
e.
Bottom Elevation, FMSL:
28.0
29.0
29.4
f.
Bottom Surface Area, ft2:
3,395
4,830
3,590
g.
Bypass Weir Elevation, FMSL:
30.0
30.5
30.5
h.
Permitted Storage Volume, ft3:
7,675
8,265
6,765
i.
Type of Soil:
Seagate
j.
Expected Infiltration Rate, in/hr:
12.0
k.
Seasonal High Water Table, FMSL:
26.0
27.0
27.4
I.
Time to Draw Down, hours:
<3
<10
<7
M.
Receiving Stream/River Basin:
Howe Creek / Cape Fear
n.
Stream Index Number:
18-87-
0.
Classification of Water Body:
"SA ORW"
(project is outside the 575' AEC)
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 facilities shall be constructed as shown on the approved plans. This permit
shall become voidable unless the facilities are constructed in accordance with
the conditions of this permit, the approved plans and specifications, and other
supporting data.
4. 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.
Page 3 of 7

State Stormwater Management Systems
Permit No. SW8 051217
5. The permittee shall at all times provide the operation and maintenance
necessary to assure the permitted stormwater system functions at optimum
efficiency. The approved Operation and Maintenance Plan must be followed in
its entirety and maintenance must occur at the scheduled intervals including, but
not limited to:
a. Semiannual scheduled inspections (every 6 months).
b. Sediment removal.
C. Mowin.9 and revegetation of slopes and the vegetated filter.
d. Immediate repair of eroded areas.
e. Maintenance of all slopes in accordance with approved plans and
specifications.
f. Debris removal and unclogging of bypass structure, infiltration media, flow
spreader, catch basins, piping and vegetated filter.
g. A clear access path to the bypass structure must be available at all times.
6. Records of maintenance activities must be kept and made available upon
request to authorized personnel of DWQ. The records will indicate the date,
activity, name of person performing the work and what actions were taken.
7. 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.
8. Access to the stormwater facilities shall be maintained via appropriate
easements at all times.
9. 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.
10. The permittee shall submit final site layout and grading plans for any permitted
future areas shown on the approved plans, prior to construction.
11. A copy of the approved plans and specifications shall be maintained on file by
the Permittee for a minimum of ten years from the date of the completion of
construction.
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.
Page 4 of 7

State Stormwater Management Systems
Permit No. SW8 051217
III. GENERAL CONDITIONS
This permit is not transferable except after notice to and approval by the Director.
In the event of a change of ownership, or a name change, the permittee must
submit a formal permit transfer request to the Division of Water Quality,
accompanied by a completed name/ownership change form, documentation
from the parties involved, and other supporting materials as may be appropriate.
The approval of this request will be considered on its merits and may or may not
be approved. The permittee is responsible for compliance with all permit
conditions until such time as the Division approves the transfer request.
2. Failure to abide by the conditions and limitations contained in this permit may
subject the Permittee to enforcement action by the Division of Water Quality, in
accordance with North Carolina General Statute 143-215.6A to 143-215.6C.
3. The issuance of this permit does not preclude the Permittee from complying with
any and all statutes, rules, regulations, or ordinances, which may be imposed by
other government agencies (local, state, and federal) having jurisdiction.
4. In the event that the facilities fail to perform satisfactorily, including the creation
of nuisance conditions, the Permittee shall take immediate corrective action,
including those as may be required by this Division, such as the construction of
additional or replacement stormwater management systems.
5. The permittee grants DENR Staff permission to enter the property during normal
business hours for the purpose of inspecting all components of the permitted
stormwater management facility.
6. The permit may be modified, revoked and reissued or terminated for cause. The
filing of a request for a permit modification, revocation and reissuance or
termination does not stay any permit condition.
7. Unless specified elsewhere, permanent seeding requirements for the stormwater
control must follow the guidelines established in the North Carolina Erosion and
Sediment Control Planning and Design Manual.
8. Approved plans and specifications for this project are incorporated by reference
and are enforceable parts of the permit.
9. The permittee shall notify the Division any name, ownership or mailing address
changes within 30 days.
Permit issued this the 22"d day of August, 2008.
NORTXCAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
Division of Water Quality
By Authority of the Environmental Management Commission
Permit Number SW8 051217 Modification
Page 5 of 7

OFFICE USE ONLY
11 Date Received
Fee Paid
Permit Number11
11 -off-
aD• DO
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This form may be photocopied for use as an original
1. GENERAL INFORMATION
1. Applicants name (specify the name of the corporation_ individual, etc. who owns the project):
2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance):
3. Mailing _Address for person listed in item 2 above:
U (._a. o LA V\tx_- p5Q/_? CalfSC�,
City: State: kc— Zip: Z&AI2—
Telephone Number:
4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans,
specifications, letters, operation and maintenance agreements, etc.):
08at,-YI C_11._IZLJt �^tr� G2c FFou�
5. Location of Project (street address):
City: County:
6. Directions to project (from nearest major intersection):
7. Latitude: 2� � 0 f LDt Longitude: —I .4 9, 1 1�5
n of project
8. Contact person who can answer questions about the project:
Name: {'.V11-.e anJGDTT Telephone Number: � (q�� �I — (P
II. PERMIT INFORMATION:
1. Specify whether project is (check one): New Renewal _Modification
Form SWU-101 Version3.99 Pagc 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 number ' GjW S n5121 and its issue date (if known) }yyh hj(.p
3. Specify the type of project (check one)
Low Density High Density Redevelop Ceneral Permit Other
4. Additional Project Requirements (check applicable blanks):
_CAMA Major Sedimentation/Erosion Control _404/401 Permit NPDES Stormwater
Information on required state permits can be obtained by contacting the Customer Service Center at
1-877-623-6748.
III. PROJECT INFORMATION
1. In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative
(one to two pages) describing stormwater management for the project .
2. Stormwater runoff from this project drains to the �61r . cme2 -• River basin.
3. Total Project Area: 10• 1 2Z acres
5. How many drainage areas does the project have? 13
4. Project Built Upon Area: 39).1 %
6. Complete the following information for each drainage area. If there are more than two drainage areas in the
project, attach an additional sheet with the information for each area provided in the same format as below.
Basin Information
Drainage Area 5 l
Drainage Area 132•,
Receiving Stream Name
Receiving Stream Class
Drainage Area
z„Z L
Existing Impervious* Area
Q
Proposed Impervious"Area
(p7 ZQ S
% Impervious* Area (total)
I(Q , Q '/ .
Impervious* Surface Area
Drainage Area f5I
Drainage Area$2,
On -site Buildings
cn5
H 2 '0'J•k
On -site Streets
0O
On -site Parking
;Z O O S•
Z5 ( D C2.
On -site Sidewalks
C- C7 - 11 -
g.p,
Other on -site
Off -site
Q
0
Total: ZO
Total: CJ Stv°I7d
* Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
sidewalks, gravel areas, etc.
Form SWU-101 Version 3.99 Page 2 of

1
Basin Information
Drainage Area " L
age Are
Receiving Stream Name
Receiving Stream class
Drainage Area
,
Pxlsting impervious` Area
Proposed Impervious'Area
51 O S•
% Impervious` Area (total)
Impervious* Surface Area
Drainage Area L
Or age Area
On -site Buildings
lb,sao S, r--
On -site Streets
O
On -site Parking
S21:�,
On -site Sidewalks
O S
Other on -site
Off -site
Total: ( 03 O
Total:
Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
sidewalks, gravel areas, etc.
Form SWU-101 Version 3.99 Page 2 of 4

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

VI. SUBMITTAL REQUIREMENTS
Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ).
A complete package includes all of the items listed below. The complete application package should be
submitted to the appropriate DWQ Regional Office.
Please indicate that yen have provided the following required information by initialing in the spare provident
next to each item.
Initials
• Original and one copy of the Smrmwater Management Permit Applicatinn Form RZ 2
• One copy of the applicable Supplement Fornt(s) for each BMP N/A
• Permit application processing fee of $420 (payable to NCDENR) NfA
• Detailed narrative description of sturmwaier treamnent/utanagement w/s.
• Two copies of plans and specifications. including: 42-S
- Development/Project name
- Engineer and firm
- Legend
- North arrow
- Scale
- Revision number & elate
Mean high water line
Dimensioned property/project boundary
Location map with named streets or NCSR numhers
Original contours, proposed contours, spot elevations, finished floor elevations
Details of roads, drainage features, collection systems, and stoI'll lwater control measures
Wetlands delineated, or a note on plans that none exist
Existing drainage. (including off -site), drainage easemen(s, pipe sizes, runoff calculations
Drainage areas delineated
Vegetated buffers (where required)
VII. AGENT AUTHORIZATION
If yen wish to designate authority to another individual or firm so that they may provide information on your
behalf, please complete this section.
Designated agent (individual or firm):Pe—rt-.-P. ✓C CFrr) CL-44 PE--:4 &1-4 PA, .
Mailing Address: C200r14- I:21�, T
'' UI.2- 5I0
City: State: N(✓ Zip:
Phone: ( 11°7 ) I9-(O-7IL4
Vill. APPLICANT'S CERTIFICATION
rax: ( °I I] ) -319 —151 (�o
1, (print or rype name of person listed in General Information. item Z) C--r1 r.P}n 1.
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 projecl complies with the requirements of ISA
NCAC 7H lom(h
Date: �12
Pond SWU-101 Version 3.99 Page 4 of 4

P. 01
TRANSACTION
REPORT
SEP-23-2008 Tl1E 09 : 35 AM
FOR: NCDENR
910
350 2004
t SEND
DATE START RECEIVER
TX TIME
PAGES TYPE
NOTE M# DP
SEP-23 09:33 AM 94522899
2'07"
6 FAX TX
OK 239
TOTAL : 2M 7S PAGES: 6
State of North Carolina
Department of Environment and Natural Resources
Wilmington Regional Office
Michael F. Easley, Governor
FAX COVER SHEET
Daze:
To:
��d/jo
Co;
Wdliam G. Ross, Jr., Secretary
No. Pages (excl. cover): -�
From: Jo Casmer
Phone: [phone]
Fax: �27 _ 2 S- ? % Fax» (91.0) 350-2004
Re: �6 OEtJ Z7 Z /rl E n r /i --j/ -:5,1V / -7
O'Xn' /1�172 i
/79od:�•�,-t7/o-✓ :// -7/-Zz-2oo8.
127 Cardinal Drive Extension, Wilmington, NC 28405 • [phone] • An Equal Opportunity Affirmative Action Employer
4
v

State of North Carolina
v Department of Environment and Natural Resources
Wilmington Regional Office
Michael F. Easley, Governor William G. Ross, Jr., Secretary
FAX COVER SHEET
Date: //2No. Pages (excl. cover):
To: � U From: Jo Casmer
Co: �oU7�I�/i/ �/l✓i/o�/n�irrPhone: [phone]
Fax:S2 — Z % Fax: [phone]
Re: �G OEnJ EnI E n i /� SGU 8DS/� / %
�o�o� o���n /� r r��/fr d - Gft -/ E�5 �
127 Cardinal Drive Extension, Wilmington, NC 28405 • [phone] • An Equal Opportunity Affirmative Action Employer

CLH design, p.a.
MacGregor Park, 125Edinhurgh South, Suite 310
Cary, North Carobi is 27511
Phone: [phone] Fax: [phone]
Email. [e-mail]
LETTER OF TRANSMITTAL
To:
Rhonda Hall
Company: NCDENR Water Quality Section
Address: 127 Cardinal Drive
City, State Zip: Wilmington, NC 28405
Phone: [phone]
Fax: [phone]
1-Oct-07
Method:
Subject:
® Prints
® Reports
UPS Ground
Ogden Elementary School -Mobiles
❑ Originals ❑ Specifications
❑ Copy of Letter ❑ Submittals
CLH Project Number: 1217-prmt
® Applications
❑ Other:
We are sending you the following items:
No of Copies Date
Description
• 2
1-Oct-07
Revised Sheet C3.1
•
•
IrD
lQ f� Ti
OCT 0 2 1007
Additional Remarks:
Rhonda,
Attached is the revised sheet C3.1. Vincent Lewis' name has been taken off the plans per your request. I
look forward to your approval of this project. Thanks for your help.
Please call me at [phone] if you have any questions.
Signed
.9en4e scotf U0
cc: File

CLH design, p.a.
MacGregor Park, 129 Edinhurgh South, Suite 310
Cary, North Carolina 27911
Phone: [phone] Fax: [phone]
Emai/. clhdesignoclhdesignpa.com
LETTER OF TRANSMITTAL
To: Linda Lewis
Company: NCDENR Water Quality Section
Address: 127 Cardinal Drive
City, State Zip: Wilmington, NC 28405
Phone: [phone]
Fax: [phone]
Method: UPS Air
16-Jul-07
Subject: Ogden Elementary School -Mobiles CLH Project Number: 1217-prmt
E
E
Prints
Reports
❑ Originals
❑ Copy of Letter
❑ Specifications ® Applications
❑ Submittals ❑ Other:
We are sending you the following items:
No. of Copies Date
Description
•
2
17-Jul-07
Modified Stormwater permit applications
•
2
17-Jul-07
Calculations I Narrative
•
1
17-July-07
Regular Permit Fee ($420.00)
•
2
17-Jul-07
Sets of Plans
Additional Remarks
Please review the attached documents for DWQ approval for the modification to Ogden Elementary
School. No design elements of infiltration basin B2 have changed. I trust this information is sufficient for
your review.
Please call me at [phone] if you have any questions.
Signed
Renee Scott
cc: File
REC LIVF,D
JUL 1 S 2007
BY:

CLH design, p.a.
MacGregor Park, 129 Edinburgh South, Suite 310
Cary; North Carolina 27511
Phone: [phone] Pax [phone]
17-July-07
TO: Linda Lewis- Division of Water Quality -Modification to Application No. SW8 051217
FROM: Renee Scott
RE: REGULAR REVIEW
OGDEN ELEMENTARY SCHOOL
CC: File (1217-prmt)
Dear Ms. Lewis,
Attached is a permit modification to the above mentioned project. The calculations attached prove the
B2 basin designed under the original storm water permit can handle the additional BUA from the mobiles
that will be located on site. Please refer to the plans for these mobile locations. Basin B2 has not been
modified from the previous storm water permit (SW8 051217), therefore no detail sheets have been
submitted with this package.
Please let us know if you should have any questions.
Sincerely,
Renee Scott
MW if..tun Cover Ulm,d.

DESIGN CALCULATIONS
CnnL✓S1TE WORK
OGDEN ELEMENTARY SCHOOL
3637 MIDDLE SOUND LOOP ROAD
NEW HANOVER COUNTY, NC
JuLY, 2007
CLH design, p.a.
MacGrggor Park, 125 Edinburgh South, Suite 310
Cary, North Carolina 27511
Phone: [phone] Fax: [phone]

CONTENTS
STORMWATER DESIGN NARRATIVE
CALCULATIONS
STORMWATER MANAGEMENT

STORMWATER MANAGEMENT

Stormwater Management Narrative
Ogden Elementary School
July, 2007
The site is located on Middle Sound Loop Road approximately one half mile east of NC Highway 17.
There is an existing elementary school with multiple classroom buildings and site infrastructure. A new
elementary school building is proposed to replace the existing buildings currently on site. The site work
Will include new bus and parent loops and new driveway access. Some of the current school buildings
remain occupied and the school will remain operational during the project.
The project is located within the Howe Creek watershed which is designated as SA waters. Wetlands
encroach on site and are indicated on the plans: No streams are shown on USGS Quad maps or soil
survey mapping. No wetlands are impacted by this project.
The proposed site impervious area (which is 41.7% of the site) will require the site to meet High Density
requirements. Due to the location of the project within areas in SA waters, the stormwater shall be
treated in infiltration basins. The stormwater infiltration basins will be reviewed by NCDENR DWQ and
New Hanover County. The basins provide both stormwater treatment and detention.
Stormwater Treatment Requirements
The infiltration basins will treat the first 1.5 inches of runoff. Due to the shallow Seasonal High Water
Table, some fill will be required to meet the 2 foot minimum infiltration layer. The soils provide
infiltration rates of 2.4 in/hr (see attached soils infiltration evaluation by ECS). Pre-treatment of
stormwater prior to entering infiltration basin will be provided by sand filters and sediment basins.
Pre / Post Development Runoff
The temporary storage capacity of the infiltration basins and pre-treatment devices will be utilized to
provide detention volume required to reduce the post -development runoff from the site to a peak rate less
than the pre -development rate for the 2-yr, 10-yr and 25-yr 24-hr storm event.
Detention hydrographs and pond routing calculated with Hydraflow Hydrographs 2002 version 7.0 by
Intelisolve software.
Pre / Post Development Runoff Summary
Drainage Basin Area A
Description: Southern portion of the site draining to the southern corner of the
properly adjacent to the
Brandywine subdivision. Run-off enters wetland prior to leaving the property.
No additional off -site
drainage enters Area `A'.
Summary
Pre -Development Post -Development
With Detention
DA (ac) 2.80 0.59
CN 53.8 38.0
Tc (min) 5.0 5.0
Peak Q2 (efs) 1.6 0.5
N/A
Peak Q10 (efs) 6.3 0.2
N/A
Peak Q25 (cfs) 8.8 0.01
N/A
No detention necessary for Drainage Basin Area A.
Drainage Basin Area B
Description: Western portion of the site draining to the western property line.
Run-off enters wetland
prior to leaving the property. No additional off -site drainage enters Area `B'.

Summary
Pre -Development
Post -Development
With Detention
DA (ac)
3.23
6.97
CN
58.1
64.0
Tc (min)
5.0
5.0
Peak Q2 (cfs)
2.9
9.9
0.7
Peak Q10 (cfs)
9.2
25.2
5.6
Peak Q25 (cfs)
12.2
32.3
8.9
Detention is provided by Infiltration Basins `B1' and `B2'.
Drainage Basin Area C
Description: Eastern portion of the site draining to the right-of-way of Middle Sound Loop Road. No
additional oft -site drainage enters Area `C'.
Summary
Pre -Development
Post -Development With Detention
DA (ac) 4.09
2.56
CN 47.3
67.9
Te (min) 5.0
5.0
Peak Q2 (cfs) 0.7
4.6 0.5
Peak Q10 (cfs) 5.8
10.6 5.4
Peak Q25 (cfs) 8.8
13.3 8.5
Detention is provided by Infiltration Basin `C'.
Total Site
Summary
Pre -Development Post -Development With Detention
Q2 (cfs) 5.2 14.4 1.1
Q10 (cfs) 21.3 36.0 11.1
Q25(efs) 29.7 46.1 17.9

W111E
® SM] CL YN
-Mt-Nb-ml
Ate@ R-Ip
WR.1
L6 JIY Po ]A\
Rpulsml-mlo am
m nm z l02
zam - o
GRAP SCALE
;Bawyw
�ve�d@mcRs;
Fp...1.
124 M ,.
,NrYryp. MC 28
f�
Ogden
Elementary
School
Replacemeni
Project # 820-9113
3637 Middle Sound RoE
STORMWATER
MANAGEMENT
PRE -DEVELOPMENT
OMNA6E
AREAS

R,R
mmr
m vuwu.
xwri.-me-msao
rbm - o
O
I
xA\
xvxxr TTT/'
m nawne� t
RbIrS-ni-an-M E
zoc¢ R-m
X�
x
m uw w for
w..n-on-Minim imm
INRLTRA77C
POND 'C'
AREA 'A'
a'
I
r 0
JJ
All efr�
e
AREA 'C'
-\ mBAOf
.. mm�wmv
AREA 'C
BYPASS
GRAPHIC scA
�inX �rR
Rwis on'-ar
a
INFILTRATION
POND 'B1'
__ Rw.ao-msRns-Poo /
1r
� I 7
06 NIS w bN
o-me-xw-a
A(A R-If
A/ mrmwnn
.a.m-am-u�mo
PR�]^OSD R6N
usAoxsxm+rs �
/
�'AREA 'B'
BYPASS
,INFILTRATION
POND '82'
i
1VIROPFNFxmi$ By x000!
John
sawyw
�vasc�si
P.O. Bu fR
1i. MXMX�sI
NFnwbM1 NC iBGU1
I. G10.lO2ST
e: N�IX.�:OmLaRITI
Ogden
Elementary
School
Replacemeni
Project # 820-9113
3637 Middle Sound Roa
PMYvu'
STORMWATER
MANAGEMENT
POST -DEVELOPMENT
DRAiN -W

�---%a
INFx TRA T/ON BAS/N BZ

STOMNAVATER ANALYSIS - OGDEN F.LEMENTARY SCHOOL
AREA 131 - PORTION OF SITE ENTERING POND
Site Area =
2.24 ac Te
Wt. CN =
76.7
Site Soils:
Seagate/Murville
12=
5.87 in/hr
110=
7.24 inflr
125=
8.15 in/hr
Wooded Area:
Impervious Area:
Lawn Area:
Weighted C:
Site Arm =
3.17 ac Te
Wt. CN =
66.0
Site Soils:
Seagate/Murville
12=
5.87 in/hr
110=
7.24 in/hr
125=
8.15 in/hr
Wooded Area:
Impervious Arm:
Lawn Area:
Future Impervious
Area:
Weighted C:
Site Arcs =
1.56 ac Tc
Wt. CN =
41.9
Site Soils:
Seagate/Murville
12=
5.87 in/hr
110=
7.24 in/hr
125=
8.15 in/hr
Wooded Area:
Impervious Arm:
Lawn Area:
Weighted C:
= 5.00 min
Qa25
= 14.24 efs
Qal0
= 11.74 cfs
(Hydrologic Soil Group A) Qa2
= 5.94 cfs
0.00 ac CN=
36
1.43 ac CN=
98
0.81 ac CN=
39
76.7
=
5.00 min
Qa25
= 15.59 cfs
Qa10
= 12.29 cis
(Hydrologic Soil Group A) Qa2
= 5.08 cis
0.00 ac
CN=
36
1.26 ac
CN=
98
1.72 ac
CN=
39
0.19 ac
CN=
98
66.0
= 5.00 min
Qa25 =
2.13 cfs
Qa10 =
1.21 cis
(Hydrologic Soil Group A) Qa2 =
• 0.07 cfs
0.83 ac CN=
36
0.12 ac CN=
98
0.61 ac CN=
39
41.9
98 000a &IW1217-P-MAnely^le'moeoas.xLS oxmea: 711 fi@OW 10sn nm Page 1 of t

G
DATE
2/7/06
PROJECT NAME
PROJECT NO
Ogden Elementary School
1217
u
l v
LOCATION
BY
New Hanover County
KAL
Drainage Area, (DA) =
3.17 ac
Impervious Area (c=0.95) =
1.45 ac
Pervious Area (c=0.35) =
1.72 ac
Cc =
0.62
Infiltration Basin
% Impervious =
46 %
Soil Infiltration Rate =
2.40 in/hr
Design Storm Rainfall
1.50 in
(Typically 1-in)
Runoff Coeff. (Rv = 0.05 + 0.009 (% Imperv.)) =
0.46 in/in
Required Volume (design rainfall)(Rv)(DA) =
7,969 cf
Volume Provided:
8,265 cf
Proposed depth of infiltration device:
1.50 ft
Avg. Surface Area Required:
5,313 sf
Full Depth Surface Area Provided:
4,831 sf
Pretreatment
% of required volume requiring pretreatment =
50 %
Volume of pretreatment device=
3,984 cf
Drawdown
Soil Infiltration Rate =
2.40 in/hr
Proposed depth of infiltration device:
1.50 ff
Drawdown Time: (Vol/Area*Rate)=
8.6 hrs
0.36 days
s:\1319\0001\celcs\1217-PondSlze-Pond B2. Mobiles XLS printed: 7116200710:56 AM Page 1 of 1

e
Reservoir Report
Page 1
Reservoir No. 3 - POND B2 Hydraflow Hydrographs by Intelisolve
Pond Data
Pond storage is based on known contour areas. Average end area method used.
Stage I Storage Table
Stage (ft)
Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
0.00
29.00
4,830
0
0
1.00
30.00
17,910
11,370
11,370
2.00
31.00
27,885
22,898
34,268
3.00
32.00
81,000
54,443
88,710
Culvert I
Orifice Structures
Weir Structures
[A]
[B]
[C]
[D]
[A] [B]
[C]
[D]
Rise in
= 15.0
0.0
0.0
0.0
Crest Len ft
= 0.00 0.00
0.00
0.00
Span in
= 15.0
0.0
0.0
0.0
Crest El. ft
= 0.00 0.00
0.00
0.00
No. Barrels
= 1
0
0
0
Weir Coeff.
= 3.33 0.00
0.00
0.00
Invert El. ft
= 30.50
0.00
0.00
0.00
Weir Type
= - --
---
--
Length It
= 84.0
0.0
0.0
0.0
Multl-Stage
= No No
No
No
Slope e/
= 4.07
0.00
0.00
0.00
N-Value
= .013
.013
.000
.000
Orif. Coeff.
= 0.60
0.60
0.00
0.00
Multistage
= n/a
No
No
No
Exfiltratlon Rate
= 0.52 in/hr/sgft Tailwater Elev.
= 0.00 ft
Note. All Duffles have been analyzed unow inlet antl outlet control.
Stage / Storage / Discharge Table
Stage
Storage Elevation
Clv A Clv
B Clv
C Clv D Wr A
Wr B Wr C
Wr D
Exfil
Total
ft
cuft It
cis
cis
cfs
cis cis
cis cis
cfs
cis
cfs
0.00
0 29.00
0.00
---
--
- ---
--- ---
---
0.000
0.00
1.00
11,370 30.00
0.00
--
---
-- --
-- --
---
0.216
0.22
2.00
34,268 31.00
1.10
--
---
-- --
-- --
---
0.336
1.44
3.00
88,710 32.00
5.53
---
---
--- ---
--- ---
---
0.975
6.50

Hydrograph Plot
Hyd. No. 11
AREA B2 TO POND
Hydrograph type
Storm frequency
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration.
= SCS Runoff
= 2 yrs
= 3.17 ac
= 0.0 %
USER
= 4.50 in
= 24 hrs
Hydmflow Hydrographs by Inteltsolve
Peak discharge = 5.08 cfs
Time interval =
1 min
Curve number =
66
Hydraulic length =
0 ft
Time of conc. (Tc) =
5 min
Distribution =
Type III
Shape factor =
484
Hydrograph Volume = 16,546 cult
11 - SCS Runoff - 2 Yr - Qp = 5.08 cfs
6
N
w.
V
C'1
0.0 2.4 4.8 7.2 9.6 12.0 14.4 16.8 19 .0
Time (hrs)
® Hyd. 11
5
-
4
3
2 —
1 -
0
.2 21.6 24

Hydrograph Plot
Hyd. No. 11
AREA B2 TO POND
Hydrograph type
Storm frequency
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
= SCS Runoff
= 10 yrs
= 3.17 ac
= 0.0 %
= USER
= 7.00 in
= 24 hrs
Hydraflow Hydrographs by Intelisolve
Peak discharge = 12.29 cfs
Time interval =
1 min
Curve number =
66
Hydraulic length =
0 ft
Time of conc. (Tc) =
5 min
Distribution =
Type III
Shape factor =
484
Hydrograph Volume = 37,980 cult
11 - SCS Runoff -10 Yr - Qp = 12.29 cfs
15
10
w
Cl
5
0
0.0 2.4 4.8 7.2 9.6 12.0 14.4 16.8 19.2 21.6 24.0
Time (hrs)
® Hyd. 11

Hydrograph Plot
Hyd. No. 11
AREA B2 TO POND
Hydrograph type
Storm frequency
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
= SCS Runoff
= 25 yrs
= 3.17 ac
= 0.0 %
= USER
= 8.05 in
= 24 hrs
Hydraflow Hydrographs by Intelisolve
Peak discharge = 15.59 cfs
Time interval =
1 min
Curve number =
66
Hydraulic length =
0 ft
Time of conc. (Tc) =
5 min
Distribution =
Type III
Shape factor =
484
Hydrograph Volume = 47,987 cult
11 - SCS Runoff - 25 Yr - Qp = 15.59 cfs
20
15
rn
w
� 10-
CY
5
0
0.0 2.4 4.8 7.2 9.6 12.0 14.4 16.8 19.2 21.6 24.0
Time (hrs)
® Hyd. 11

Hydrograph Plot
Hyd. No. 11
AREA B2 TO POND
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Drainage area
= 3.17 ac
Basin Slope
= 0.0 %
Tc method
= USER
Total precip.
= 10.00 in
Storm duration
= 24 hrs
25
2
r� 1
1
Hydraflow Hydrographs by Intelisolve
Peak discharge = 21.94 cfs
Time interval =
1 min
Curve number =
66
Hydraulic length =
0 ft
Time of conc. (Tc) =
5 min
Distribution =
Type III
Shape factor =
484
Hydrograph Volume = 67,537 cuft
11 - SCS Runoff - 100 Yr - Qp = 21.94 cfs
0
—
5
0
5 -
0
0.0
2.4 4.8 7.2 9.6 12.0 14.4 16.8 19.2 21.6 24.0
Time (hrs)
O Hyd. 11

Re: Ogden Elementary School (SW permit no. SW8 051217)
Subject: Re: Ogden Elementary School (SW permit no. SW8 051217)'
From: Linda Lewis <[e-mail]>
Date: Wed, 11 Jul 2007 10:42:47 -0400
To: Renee Scott <[e-mail]>
Renee:
All modifications use the same application forms as a new project would. You need
to complete a new application SWU-101 showing the information for all of the
unchanged basins and the revised BUA information for the basin(s) that will be
changing. An original signature on the application is required. We cannot "reuse"
the previous signature page for a modification.
Additionally, a signed and revised supplement form will be needed if any of the
permitted design elements of the basin(s) will be revised.
Two sets of plans are required for all new or modified projects. As an
environmental agency, we encourage conservation by encouraging you to submit only
the revised sheets rather than the entire set, but only if the revised sheets show
all of the unchanged previously permitted information plus the new revised
information. Please remember to include the detail sheet if the detail sheet
changes.
In order to demonstrate that the basin(s), as previously permitted, can handle the
additional BUA, you will need to provide signed, sealed and dated calculations for
the revised basin(s) only, as if the basin(s) was being designed from scratch,
using the increased BUA.
Linda
Renee Scott wrote:
Linda,
I am getting ready to submit a permit modification for the above
mentioned
project. I have a couple of questions.
1. Is there a permit modification form I need to fill out or do I
just have
a cover letter stating that the attached information is a
modification to
permit no. SW8 051217?
2,. Do you need to see the entire application again or is it just
the sheets
that will be modified based on the changes? If you do need to see
the
entire application again, do I need to get it signed by the owner
again?
3. How many sets of plans do you need to see?
4. I have supporting calculations showing the increase in BUA. Do
you need
to see our entire calculations for the infiltration basin that the
additional BUA will be flowing to or just the supporting
calculations
proving that the infiltration basin can handle the additional BUA?
Please let me know as soon as possible, I would like to send the
information
1 'of4 7/11/2007 12:26 PM

Re: Ogden Elementary School (SW permit no. SW8 051217)
0
to you in the next couple of days.
Thanks!
Renee
-----Original Message -----
From: Linda Lewis [mailto:[e-mail]] Sent: Wednesday,
June 06, 2007 3:13 PM
To: Renee Scott
Subject: Re: Ogden Elementary School (SW permit no. SW8 051217)
Renee:
You need to submit a permit modification. The additional BUA needs
to be
added to the application and you need to demonstrate that the basin
as
designed can accommodate the increased BUA.
May I suggest that when you oversize a pond or basin for a future
project,
please be sure to add the additional BUA to the application as a
"contingency" amount. That will make the modification process much
smoother
and quicker (for both of us!!)
Linda
Renee Scott wrote:
/Linda,/
/I am contacting you concerning Ogden Elementary
School in New Hanover County. I received a storm
water permit from your office in February of 2006
(Stormwater Permit No. SW8 051217). As you may
recall, this project drained to SA waters and was a
high density site. We treated the water runoff
with infiltration basins./
/When we permitted the stormwater, there were no
mobile units planned to be located on site.
Recently we received a request from New Hanover
County Schools for 3 mobile units to be located on
site for the upcoming school year./
/I immediately looked at our stormwater spread
sheets to see how this effects our basins and
impervious area. The runoff for these new mobile
units would drain to infiltration basin B2, see
attached plan.
� 2 of 4 7/11/2007 12:26 PM

Re: Ogden Elementary School (SW permit no. SW8 051217)
These mobile units would produce an additional .10
acres or 4,356 s.f. of additional impervious area.
In our calculation spread sheets we oversized the
Infiltration Basin B2 for an additional .30 acres
of future impervious area. If we add .09 acres of
impervious area from the new mobiles, then the
basin can still accommodate an additional .20 acres
of impervious area in the future. See the attached
application sheet with redline markups and also our
calculations for this basin./
/One complication we ran into was that when we
filled out the Storm Water Management Permit
Application Form , section III, Drainage Area B2,
under proposed impervious area we did not account
for this "future impervious", because it
technically is not in the project and there
were no breakout lines for "future impervious".
/The question I have is what do we need to do as
far as these revisions are concerned to still be in
accordance with this permit?/
/Please let me know as soon as possible. There is
somewhat of a time crunch to get these mobiles
located./
/Thanks,/
/Renee/
/*Renee C. Scott*/
/*Project Manager*/
/*CLH Design, P.A.*/
/*125 Edinburgh South Drive*/
/*Suite 310*/
/*Cary, NC 27511*/
/*P: [phone] F: (919)
<< ... >> << ... >> /
319-7516*/ / << ... >>
3 of 4
7/11/2007 12:26 PM