SW8990546_CURRENT PERMIT_20230308

STORMWATER DIVISION CODING SHEET
POST-CONSTRUCTION PERMITS
PERMIT NO. SW8 OVg05�U
DOC TYPE I CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE 7-0 2 3 03 0-s
YYYYMMDD

STATC
ROY COOPER = `
Governor
ELIZABETH S.BISER
Secretary
DOUGLAS R.ANSEL NORTH CAROLINA
interim Director Environmental Quality
March 8, 2023
New Hanover County Schools
Attn: Edward J. Anderson,Assistant Superintendent
6410 Carolina Beach Road
Wilmington,NC 28412
Subject: Permit Renewal
Post-Construction Stormwater Management Permit No. SW8990546
Williston Middle School
New Hanover County
Dear Mr. Anderson:
The Division of Energy, Mineral and Land Resources received a complete 8-year Permit Renewal Application for
the subject permit on March 6,2023. The Division is hereby notifying you that permit SW8990546 has been
renewed, updated, and re-issued on March 8, 2023,as attached. Please be aware that the renewal and re-issuance
of this stormwater permit does not imply that the site is currently in compliance.
This permit shall be effective until August 14,2030 and does not supersede any other agency permit that may be
required. The project shall be subject to the conditions and limitations as specified therein. This permit does not
impose new or increased stormwater control requirements; it clarifies the rules and requirements of this program
to provide you with a better understanding of your obligations under this permit. Failure to comply with these
requirements will result in future compliance problems. Please note that this permit is not transferable except
after notice to and approval by the Division.
If any parts, requirements, or limitations contained in this permit are unacceptable, you have the right to request
an adjudicatory hearing by filing a written petition with the Office of Administrative Hearings (OAH). The
written petition must conform to Chapter 150B of the North Carolina General Statutes and must be filed with the
OAH within thirty (30)days of receipt of this permit. You should contact the OA14 with all questions regarding
the filing fee(if a filing fee is required)and/or the details of the filing process at 6714 Mail Service Center,
Raleigh,NC �27699-6714,or via telephone at 919-431-3000, or visit their website at www.NCOAH.com. Unless
such demands are made this permit shall be final and binding.
If you have any questions concerning this permit, please contact Aisia Freeman in the Wilmington Regional
Office, at phone# [phone] or [e-mail].
Sincerely,
Douglas R. Ansel, Interim Director
Division of Energy,Mineral and Land Resources
Enclosures: Attachment C—Permitting History
Copy of the Renewal Application Documents
DES/af: \\\Stormwater\Permits&Projects\1 999\990546 HD\2023 03 permit 9905,16
cc: Doug Haggett,PE;Haggett Engineering Associates,Inc.
Wilmington Regional Office Stormwater File
North Carolina Department of Environmental Quality I Division of Energy,Mineral and Land Resources
Wilmington Regional office I L27 Cardinal Drive Extension I Wilmington,North Carolina 28405
namN cwaur.w
Vezo910.796.7215

Post Construction Stormwater Management
Permit No. SW8990546
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF ENERGY, MINERAL AND LAND RESOURCES
POST-CONSTRUCTION STORMWATER MANAGEMENT PERMIT
HIGH DENSITY COMMERCIAL 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
New Hanover County Schools
Williston High School
401 South Tenth Street, Wilmington, New Hanover County
FOR THE
construction, operation and maintenance of one (1) wet detention pond in compliance with the provisions of
15A NCAC 2H .1000 (hereafter referred to as the "stormwater rules') as outlined in the application, approved
stormwater management plans, supplement, calculations, operation and maintenance agreement, recorded
documents, specifications, and other supporting data (the "approved plans and specifications") as attached
and/or on file with and approved by the Division of Energy, Mineral and Land Resources (the "Division" or
"DEMLR"). The project shall be constructed, operated and maintained in accordance with these approved
plans and specifications. The approved plans and specifications are incorporated by reference and are
enforceable part of this permit.
This permit shall be effective from the date of issuance until August 14, 2030 and shall be subject to the
following specified conditions and limitations. The permit issued shall continue in force and effect until the
permittee files a request with the Division for a permit modification, transfer, renewal, or rescission; however,
these actions do not stay any condition. 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 for cause as
allowed by the laws, rules, and regulations contained in Title 15A NCAC 2H.1000 and NCGS 143-215.1 et.al.
1. The original permit conditions contained in the permit issued on August 14, 2000 remain in full force
and effect, except as amended herein. (An additional copy of this original permit can be obtained
from the Division of Energy, Mineral and Land Resources, Wilmington Regional Office.)
2. The permittee shall submit a permit renewal application request at least 180 days prior to the
expiration date of this permit. The renewal request must include the applicable documentation and
the processing fee.
3. Decorative spray fountains will not be allowed in the stormwater treatment system, as the
permanent pool volume is less than 30,000 cubic feet.
Page 1 of 5

Post Construction Stormwater Management
Permit No. SW8990546
4. This permit is not transferable to any person or entity except after notice to and approval by the
Director. The permittee shall submit a completed and signed Name/Ownership Change Form,
accompanied by the supporting documentation as listed on the form, to the Division of Energy,
Mineral and Land Resources at least 60 days prior to any one or more of the following events:
a. An ownership change including the sale or conveyance of the project area in whole or in part,
except in the case of an individual lot sale that is made subject to the recorded deed restrictions;
b. The sale or conveyance of the common areas to a Homeowner's or Property Owner's
Association, subject to the requirements of Session Law 2011-256,
c. Bankruptcy;
d. Foreclosure;
e. Dissolution of the partnership or corporate entity;
f. A name change of the current permittee;
g. A name change of the project,
h. A mailing address change of the permittee;
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 1.5 of this permit. The stormwater control has been designed to handle the runoff from 97,121
square feet of impervious area.
3. Approved plans and specifications for this project are incorporated by reference and are enforceable
parts of the permit.
4. The tract will be limited to the amount of built-upon area indicated in Sections 1.2 and 1.5 of this permit,
and as shown on the approved plans.
5. The following design criteria have been approved for the wet detention pond, and must be maintained
at design condition:
a. Drainage Area, acres (all on-site): 3.11
b. Total Impervious Surfaces, ftz: 97,121
c. Pond Design Depth, feet: 3.50
d. Provided Permanent Pool Surface Area, ftZ: 10,813
e. Permanent Pool Elevation, fmsl: 37.25
f. Provided Storage Volume, ft3: 8,712
g. Temporary Storage Elevation, fmsl: 38.0
h. Controlling Orifice, inch m: 1.5
i. Receiving Stream / River Basin: Burnt Mill Creek/ CPF17
j. Stream Index Number: 18-74-63-2
k. Stream Classification: C Sw
II. SCHEDULE OF COMPLIANCE
1. The stormwater management system shall be constructed in it's 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.
Page 2 of 5

Post Construction Stormwater Management
Permit No. SW8990546
3. The permittee shall at all times provide the operation and maintenance necessary to assure the
permitted stormwater system functions at design condition. The approved Operation and Maintenance
Plan must be followed in its entirety and maintenance must occur at the scheduled intervals including,
but not limited to:
a. Semiannual scheduled inspections (every 6 months).
b. Sediment removal.
C. Mowing and revegetation of side slopes.
d. Immediate repair of eroded areas.
e. Maintenance of side slopes in accordance with approved plans and specifications.
f. Debris removal and unclogging of outlet structure, orifice device and catch basins and piping.
g. Access to the outlet structure must be available at all times.
4. Records of maintenance activities must be kept and made available upon request to authorized
personnel of the division. The records will indicate the date, activity, name of person performing the
work and what actions were taken.
5. The facilities shall be constructed in accordance with the conditions of this permit, the approved plans
and specifications, and other supporting data.
6. 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.
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. Prior to the sale of any portion of the property, an access/maintenance easement to the stormwater
facilities shall be granted in favor of the permittee if access to the stormwater facilities will be restricted
by the sale of any portion of the property.
9. The permittee is responsible for verifying that the proposed built-upon area does not exceed the
allowable built-upon area.
10. The runoff from all built-upon area on the project must be directed into the permitted stormwater control
system.
11. The Director may notify the permittee when the permitted site does not meet one or more of the
minimum requirements of the permit. Within the time frame specified in the notice, the permittee shall
submit a written time schedule to the Director for modifying the site to meet minimum requirements.
The permittee shall provide copies of revised plans and certification in writing to the Director that the
changes have been made.
Page 3 of 5

Post Construction Stormwater Management
Permit No. SW8990546
12. No person or entity, including the permittee, shall alter any component shown in the approved plans
and specifications. Prior to the constriction of any modification to the approved plans, the permittee
shall submit to the Director, and shall have received approval for modified plans, specifications, and
calculations including, but not limited to, those listed below. For changes to the project or SCM that
impact the certifications, a new or updated certification(s), as applicable, will be required and a copy
must be submitted to the appropriate DEQ regional office upon completion of the modification.
a. Any modification to the approved plans and specifications, regardless of size including the SCM(s),
BUA, details, etc.
b. Redesign or addition to the approved amount of BUA or to the drainage area.
c. Further development, subdivision, acquisition, lease or sale of any, all or part of the project and/or
property area as reported in the approved plans and specifications.
d. Altering, modifying, removing, relocating, redirecting, regrading, or resizing of any component of
the approved SCM(s), the stormwater collection system and/or vegetative conveyance shown on
the approved plan.
e. The construction of any allocated future BUA.
The construction of any permeable pavement, #57 stone area, public trails, or landscaping material
to be considered a permeable surface that were not included in the approved plans and
specifications.
f. Other modifications as determined by the Director.
III. GENERAL CONDITIONS
1. CORRECTIVE ACTIONS REQUIRED. If the facilities fail to perform satisfactorily, the permittee shall
take immediate corrective actions. This includes actions required by this Division and the stormwater
rules such as the construction of additional or replacement on-site stormwater systems. These
additional or replacement measures shall receive a permit from the Division prior to construction.
2. PERMIT RENEWAL. A permit renewal request must be submitted at least 180 days prior to the
expiration date of this permit. The renewal request must include the appropriate application,
documentation and the processing fee as outlined in Title 15A NCAC 02H.1045(3).
3. CHANGES TO THE PROJECT NAME, PERMITTEE NAME OR CONTACT INFORMATION. The
permittee shall submit a completed Permit Information Update Application Form to the Division within
30 days to making any one of these changes.
4. TRANSFER. This permit is not transferable to any person or entity except after notice to and approval
by the Director. Neither the sale of the project and/or property, in whole or in part, nor the conveyance
of common area to a third party constitutes an approved transfer of the permit.
a. TRANSFER REQUEST. The transfer request must include the appropriate application,
documentation and the processing fee as outlined in 15A NCAC 02H.1045(2). This request must
be submitted within 90 days of the permit holder meeting one or more of the following:
i. A natural person who is deceased,
ii. A partnership, limited liability corporation, corporation, or any other business association that
has been dissolved;
iii. A person or entity who has been lawfully and finally divested of title to the property on which
the permitted activity is occurring or will occur through foreclosure, bankruptcy, or other legal
proceeding.
iv. A person or entity who has sold the property, in whole or in part, on which the permitted
activity is occurring or will occur,
V. The assignment of declarant rights to another individual or entity;
vi. The sale or conveyance of the common areas to a Homeowner's or Property Owner's
Association, subject to the requirements of NCGS 143-214.7(c2);
Page 4 of 5

Post Construction Stormwater Management
Permit No. SW8990546
b. TRANSFER INSPECTION. Prior to transfer of the permit, a file review and site inspection will be
conducted by Division personnel to ensure the permit conditions have been met and that the project
and the on-site stormwater system complies with the permit conditions. Records of maintenance
activities performed to date may be requested. Projects not in compliance with the permit will not be
transferred until all permit and/or general statute conditions are met.
5. COMPLIANCE. The permittee is responsible for compliance with the terms and conditions of this
permit until the Division approves the transfer request.
a. APPROVED PLANS AND SPECIFICATIONS. A copy of this permit, approved plans,
application, supplement, operation and maintenance agreement, all applicable recorded
documents, and specifications shall be maintained on file by the permittee at all times.
b. DIVISION ACCESS. The permittee grants Division Staff permission to enter the property during
normal business hours to inspect all components of the permitted project.
c. ENFORCEMENT. Any individual or entity found to be in noncompliance with the provisions of a
stormwater management permit or the requirements of the stormwater rules is subject to
enforcement procedures as set forth in NCGS 143 Article 21.
d. ANNUAL CERTIFICATION. The permittee shall electronically submit to the Division an annual
certification completed by either the permittee or their designee confirming the projects
conformance with permit conditions
e. OBTAINING COMPLIANCE. 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
modified plans and certification in writing to the Director that the changes have been made.
f. OTHER PERMITS. The issuance of this permit does not preclude the permittee from complying
with and obtaining any other permits or approvals that are required for this development to take
place, as required by any statutes, rules, regulations, or ordinances, which may be imposed by
any other Local, State or Federal government agency having jurisdiction. Any activities
undertaken at this site that cause a water quality violation or undertaken prior to receipt of the
necessary permits or approvals to do so are considered violations of NCGS 143-215.1, and
subject to enforcement procedures pursuant to NCGS 143-215.6.
Permit renewed, updated and reissued this the 81h day of March 2023.
NORTH C�ARO�LINAA ENVIRONMENTAL MANAGEMENT COMMISSION
cam/�IXd.C.�'wL r �^�`�
.;Douglas R. Ansel, Interim Director
Division of Energy, Mineral and Land Resources
By Authority of the Environmental Management Commission
Page 5 of 5

Attachment C-Permitting History
Williston Middle School
Permit No.SW8990546
Approval Permit Action BIMS Description of the Changes Modified Plan Sheets
Date Version
6/18/1999 EXEMPTION from Storrnwater Management Permit Regulations
High Density Storrnwater Project-construction,operation and maintenance of a wet
8/14/2000 Original 1 0 detention pond in compliance with the provisions of ISA NCAC 211.1000.The Cl.l-8.2,L1.1
Approval smm rwater control has been designed to handle the runoff from 97,121 square feet of
impervious area.
High Density Project-construction,operation and maintenance of one(1)wet
5/30/2014 Renewal 2.0 detention pond in compliance with the provisions of 15A NCAC 211.1000.The
original permit conditions contained in the permit issued on August 14,2000 remain
in full force and effect,except as amended herein.
3/8/2023 Renewal 3.0 This permit shall be effective until August 14,2030
Page 1 of 1

DEMLR USE ONLY
Date i ed Fee Paid Permit Number
a5 10 10 a 505° U) '7 1 o<<
NC DEQ Division of Energy, Mineral and Land Resources
STATE STORMWATER:
PERMIT RENEWAL APPLICATION FORM
In accordance with 15A NCAC 2H.1045(3), the current permit holder shall renew their high density permit 180 days
prior to its expiration. Renewed permits are valid fora period of 8 years per Session Law 2011-398(SB 781)
Section 60.(c). This application form is for permit renewals only.
A. PROJECT INFORMATION
1. State Stormwater Permit Number: SW8 990546
2. Project name: Williston Middle School
3. Project street address: 401 S. 10th Street
City: Wilmington County: New Hanover Zip : 28401
4. What, if any, changes have been made to the project as permitted? None
If the project has changed from the original approved plans, please complete SWU-101 for a Major
Modification or Minor Modification Application form available at: hftps://deg.nc.gov/about/divisions/energy
mineral-land-resources/energy-mineral-land-rules/stormwater-grogram/post-construction.
B. PERMITTEE INFORMATION
If changes to the permittee or project name have been made, please complete either the Permit Update form
or the Permit Transfer form available at: https:Hdeg.nc.gov/about/divisions/energy-mineral-land-
resources/energy-mineral-land-rules/stormwater-program/post-construction. State Stormwater Permits do not
automatically transfer with the sale of the property.
1. Current Permit Holder's Company Name/Organization: New Hanover County Schools
2. Signing Official's Name: Edward J.Anderson
3. Signing Official's Title: Assistant Superintendent of Planning and Operations
4. Mailing Address: 6410 Carolina Beach Road
City: Wilmington State: NC Zip : 28412
5. Street Address: 6410 Carolina Beach Road
City: Wilmington State: NC Zip : 28412
6. Phone: ( 910 ) 254-4242 Email: [e-mail]
EVE M
MAR 0 6 2023
BY
Stormwater Permit Renewal Form Page 1 of 3 May 11, 2018

C. SUBMITTAL REQUIREMENTS
Submit the application package to the appropriate DEMLR Regional Office(Coastal, SA Waters) or DEMLR
Central Office(Urbanizing Areas Ph 2, USMP, Non-Coastal HQW/ORIM. Only applications packages that
include all required items listed below will be accepted and reviewed.
Initial each item below to indicate that the required information is provided in the application package:
\l' 1. A permit application processing fee of$505.00 payable to NCDEQ.
2. One original signed hard copy and one electronic copy of this completed form. The signing official
named on this application to represent the current permittee must meet one of the following:
a. Corporation—a principle executive officer of at least the level of vice-president;
b. Limited Liability Company(LLC)—a manager or company official as those terms are defined
in G.S. 57D"North Carolina Limited Liability Company Act;"
c. Public Entity—a principal executive officer, ranking official, or other duly authorized employee;
d. Partnership or limited partnership—the general partner,
e. Sole proprietor; or
I. Letter of authorization signed by one of the signatories noted in a—e above authorizing the
signature of another entity.
NA 3. One hard copy and one electronic copy of recorded documents required by the original permit that
have not yet been received by DEMLR, including: deed restrictions, protective covenants,
condominium/planned community declaration and easements. If the project has been built, include
documentation that the maximum BUA per lot or maximum total BUA has not been exceeded. If
the project has not been built, include a signed agreement that the final recorded deed restrictions
and protective covenants will be submitted at a later date.
4. O&M Agreements, Please select one:
❑ I have a copy of the current recorded 0&M Agreement for all SCMs, and I will continue to
keep this on file with the permit; or
❑ I do not have a copy of the current recorded O&M Agreement for all SCMs and am
requesting a copy be sent to me. I agree to keep this on file with the permit.
VA 5. Designer Certifications, Please select one:
0 A copy of the certification(s) confirming that the project was built in accordance with the
approved plans have been previously provided to the Division; or
❑ A copy of the certification(s) confirming that the project was built in accordance with the
approved plans are enclosed; or
❑ The project has not yet been built.
6. [IF APPLICABLE] If the project has been built, one original hard copy and one electronic copy of a
signed, sealed, and dated letter from a licensed professional stating that the SCMs have been
inspected, and that they have been built and maintained in accordance with the permit.
NA 7. [IF APPLICABLE] When the permittee is a corporation or a limited liability corporation (LLC):
Provide one hard copy and one electronic copy of documentation from the NC Secretary of State,
or other official documentation, which supports the titles and positions held by the persons listed in
Section C.2 per 15A NCAC 2H. 1043(3)(b).
his://www.sosnc.gov/online services/search/by title/ Business Registration
ECEt h1 G
MAR 0 6 2023
BY
Stormwater Permit Renewal Application Form Page 2 of 3 May 11, 2018

D. PERMITTEE'S CERTIFICATION
1 Edward J.Anderson the person legally responsible for the permit, certify that I have
a copy,of the Permit and O&M Agreement on site(or I will obtain a copy and it will be kept on site), that I am
responsible for the performance of the maintenance procedures, and the site has been and will be maintained
according to the O&M Agreement and approved plans. I agree to notify DEMLR of any problems with the SCMs
or built-upon area and to submit the proper forms to modify or transfer the permit prior to any changes to the
project, SCMs, or ownership. All information provided on this permit renewal application is, to the best of my
knowledge, correct sand complete.
Signature: GA /I A w Date: -S 7,3
NOTARIZATION:
1, IPYu e g C• 1MD(t-'S a Notary Public for the State of
North Carolina , County of New Hanover , do hereby certify
that Edward J. Anderson personally appeared before me
this the, t day of , 20,23L and acknowledge the due
execution of the forgoing instrument. Witness my hand and official seal,
.,(Notary Seal)
Ji Ot3ry Signature:
My commission expires c2- /I11 12-4,
EGE!VE
MAR 0 5 2023
BY
Stormwater Permit Renewal Application Form Page 3 of 3 May 11, 2018

Permit No. !JK/D
(to be provided by DWQ)
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopied for use as an original
DWQ Stormwater Management Plan Review:
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
I. PROJECT INFORMATION
Project Name: t1i 11 i a1-on Mi(991a Rnhonl
Contact Person: Eddie Anderson Phone Number: ( Ai0 ) 763-9431
For projects with multiple basins, specify which basin this worksheet applies to: #1
elevations
Basin Bottom Elevation 33 57 ft• (floor of the basin)
Permanent Pool Elevation 37.25 ft. (elevation of the orifice)
Temporary Pool Elevation 38.00 ft. (elevation of the discharge structure overflow) .
areas
Permanent Pool Surface Area 10,813 sq. ft. (water surface area at the orifice elevation)
Drainage Area '� i i ac. (on-site and off-site drainage to the basin)
Impervious Area 2. 73 ac. (on-site and off-site drainage to the basin)
volumes
Permanent Pool Volume 24.063 cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 36 21�; cu. ft. (volume detained above the permanent pool)
Forebay Volume 4.,987 cu. ft. (approximately 20% of total volume)
Other parameters
SA/DA1 6.4 (surface area to drainage area ratio from DWQ table)
Diameter of Orifice 1 i/2 in. (2 to 5 day temporary pool draw-down required)
Design Rainfall 1 in.
Design TSS Removal 2 90 % (minimum 85% required)
Forth SWU-102 Rev 3.99 Page 1 of 4

Footnotes:
I When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the
actual impervious %and permanent pool depth. Linear interpolation should be employed to determine the correct value for non-
standard table entries.
2 In the 20 coastal counties,the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90%TSS removal. The NCDENR BMW manual provides design tables for both 85%TSS removal and 90%TSS removal.
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management-Permit
Application Form, the agent may initial below. If a requirement has not been met,attach justification.
Ap icants Initials
t? a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
b. The forebay volume is approximately equal to 20% of the basin volume.
c. The temporary pool controls runoff from the design storm event.
d. The temporary pool draws down in 2 to 5 days.
1/4 e. If required, a 30-foot vegetative filter is provided at the outlet (include non-erosive flow
calculations)
64 £ The basin length to width ratio is greater than 3:1. .
4C4
g. The basin side slopes above the permanent pool are no steeper than 3:1.
h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
i. Vegetative cover above the permanent pool elevation is specified.
.
j. A trash rack or similar device is provided for both the overflow and orifice.
N/.4 k. A recorded drainage easement is provided for each basin including access to nearest right-
of-way.
A /JA 1. If the basin is used for sediment and erosion control during construction, clean out of the
basin is specified prior to use as a wet detention basin.
in. A mechanism is specified which will drain the basin for maintenance or an emergency.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one) 0 does 9 does not incorporate a vegetated filter at the outlet.
This system (check one) 0 does Q does not incorporate pretreatment other than a forebay.
Form SWU-102 Rev 3.99 Page 2 of 4

Maintenance activities shall be performed as follows:
I. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed:
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.)quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed
of in an appropriate manner and shall be handled in a manner that will not adversely impact water quality
(i.e. stockpiling.near a wet detention basin or stream, etc.).
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 163 feet in the main pond, the sediment shall be removed.
When the permanent pool depth reads z,.15- feet in the forebay, the sediment shall be removed:
BASIN DIAGRAM
(Fll in the blanks). -
Permanent Pool Elevation '�7__25
Sediment Re oval El. -14-80 75 0
-------------- -- Sediment Removal Elevation 39.60 75%
Bottom Ele ation ' 34.00 % --------------------------------------------- -------
Bottom Elevation 33.75 259%.
FOREBAY MAIN POND
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimized to the maximum extent practical.
Form SWU-102 Rev 3.99 Page 3 of 4

7. All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: Eddie Anderson
Title: Director of Facility Planning, Naw Hanrtwar rrn,nry scr,nnj
Address: 1802 S . 15th Street . Wilminaton . N.C . 28401
Phone: ( 910 ) 763-5431
Signature: ��o%
Date: it // /99
Note: The legally responsible party should not be a homeowners association unless more than 50%u of the lots have been sold and
a resident of the subdivision has been named the president.
I, a Notary Public for the State of 44A'M'�
County of �, do hereby certify that AVIMKW2
personally appeared before me this day of 1999 , and acknowledge the due
execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal,
SEAL
My commission expires 14 t)
Form SWU-102 Rev 3.99 Page 4 of 4

r
State Stormwater Management Systems
Permit No. SW8 990546MOD
Williston Middle School
Stormwater Permit No. SW8 990546MOD
New Hanover County
Designer's Certification
I, S C_Kq S ,as a duly registered FI?0 FG S5tby lei. E 40Ct I UFRL in '
the State of North Carolina, having been authorized to observe (periodically/weekly/full time)the construction of
the project,
_ki OmtjS AND, Uiu0Uk4t'1w5 To W« _L5-tb j MIDDLE SGvtoO( (Project)
for N6k) I'(A"uFA CyuNyY( SC#tC4L S (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:
�aam�n�
�•�`��Q��N CAR
•���4�EESS%p��'y9•
y9! SEAL
Signature
� pE qg �
2
f `
Registrati4Nber l/ ��1 •.`G...... pr`•,
•,,,cyq,s1 Fo,,,,
Date 3- 1q-03
2eCei✓¢e� �'16Yc�i /q ZC0 3
6

State Stormwater Management Systems
Permit No. S W8 990546MOD
Certification Requirements: '
I. 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.
C 4. The outlet/bypass structure elevations are per the approved plan.
C5. The outlet structure is located per the approved plans.
6. Trash rack is provided on the outletibypass structure.
7. All slopes are grassed with permanent vegetation.
C8. Vegetated slopes are no steeper than 3:1.
9. The inlets are located per the approved plans and do not cause short-circuiting of the system.
C 0. The permitted amounts of surface area and/or volume have been provided.
JCII. Required drawdown devices are correctly sized per the approved plans.
12. All required design depths are provided.
r13. All required parts of the system are provided, such as a vegetated shelf, and a forebay.
14. The overall dimensions of the system, as shown on the approved plans, are provided.
cc: NCDENR-DWQ Regional Office
Tory Roberts, New Hanover County Building Inspector
7