SW7050414_Modification_20190122

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
WILLIAM E. (TOBY) VINSON,IR
Interim Director
Washington Montessori, Inc
Attn.: Austin Smigel
2330 Old Bath Highway
Washington, NC 27889
Dear Mr. Smigel:
NORTH CAROLINA
Environmental Quality
January 22, 2019
MODIFICATION
Subject: Stormwater Permit No. SW7050414
Washington Montessori School
Low Density Project
Beaufort County
The Washington Regional Office received your completed stormwater permit
application and supporting information on January 14, 2019. 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. SW7050414 Modification dated January 22, 2019, for the construction of the
subject project. This permit modification is for the construction of a new Middle School
building and associated parking.
This permit replaces all previous state stormwater permits for this site and shall
be effective from the date of issuance until rescinded, and shall be subject to the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 and in the submitted
application. 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 150E of the North Carolina General
Statutes, and filed with the Office of Administrative Hearings, 6714 Mail Service Center,
Raleigh, NC 27699-6714. Unless such demands are made this permit shall be final and
binding.
If you have any questions, or need additional information concerning this matter,
please contact this office at [phone].
Sincerely,
Samir Dumpor, PE
Regional Engineer
cc: WARO
ec: mupeedin(cDibxengineering.com, apittman(aD_washingtonnc.gov
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North Carolina Department of Environmental Quality I Division of Energy, Mineral and Land Resources
Washington Regional Office 1 943 Washington Square Mall I Washington, North Carolina 27889
252.946.6481

State Stormwater Management Systems
Permit No, SW7050414 Modification
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF ENERGY, MINERAL, AND LAND RESOURCES
STATE STORMWATER MANAGEMENT PERMIT
LOW DENSITY DEVELOPMENT WITH AREAS OF HIGH DENSITY
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
Washington Montessori, Inc.
Washington Montessori School
Beaufort County
FOR THE
construction, operation and maintenance of an overall low density project with areas of high
density (including one infiltration basin, one infiltration trench and one bioretention basin), 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 Energy, Mineral,
and Land Resources (DEMLR) and considered a part of this permit.
This permit replaces all previous state stormwater permits for this site, and shall be effective
from the date of issuance until rescinded, 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 systems that treat the runoff from the designated high -density areas
have been approved for the management of stormwater runoff as described in Section
1.8-9 on pages 3 and 4 of this permit. The stormwater controls have been designed to
handle the runoff from 134,005 square feet of impervious area.
3. The existing stormwater treatment measures include: one infiltration basin, one
underground infiltration trench and one bioretention basin. All (3) measures are
interconnected and function as one system.
4. The overall tract built -upon area percentage for the project must be maintained at 24%
per the requirements of 15A NCAC 2H .1000 of the stormwater rules. This project site is
permitted for a maximum allowable impervious area of 368,960 square feet.
5. 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.
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State Stormwater Management Systems
Permit No. SW7050414 Modification
6. Runoff from all built -upon areas within the designated high density areas of this project
must be directed into the permitted stormwater control systems.
7. Runoff from the low density portions of this site must receive adequate treatment through
vegetated conveyances, such as maintained vegetated buffers and swales with minimum
side slopes of 3:1 (H:V) as defined in the stormwater rules, and as shown on the
approved plans.
8. The following design criteria have been provided in the infiltration basin and infiltration
trench and must be maintained at design condition:
PROJECT DATA
Project Name: Washington Montessori School
Permit Number: SW7050414 Modification
Location: Beaufort County
Applicant: Washington Montessori, Inc.
Mailing Address: 2330 Old Bath Highway, Washington, NC 27889
Receiving Stream and index No.: LIT to Broad Creek, 29-10-(1)
Classification of Water Body: C, NSW
Total Site Area: 35.44 ac
Design Storm, inches: 1.0
Drainage area: 4.19 ac (drains to infiltration basin and infiltration trench)
Allowable Impervious area for this drainage basin: 91,726 sf
Infiltration Basin Infiltration Trench
Infiltration Basin Depth: 2.5 ft 3.0 ft
Basin bottom elevation, FMSL: 16.0 15.0
Bypass Overflow Elevation, FMSL: 18.5 18.0
Type of Soil: Craven Craven
Provided Storage Volume: 13,100 cf 2,180 cf
Time to Draw Down: 2.3 days 2.4 days
Expected Infiltration Rate, in/hr: >0.52 >0.52
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State Stormwater Management Systems
Permit No. SW7050414 Modification
The following design criteria have been provided for the Bioretention cell and must be
maintained at design condition:
a. Drainage Area, acres:
b. Total Impervious Surfaces, ft2:
C. Bioretention Depth, inches:
d. Temporary Ponded Depth Elevation, FMSL:
Bioretention Bottom Elevation, FMSL:
e. Bioretention Surface Area. ft2:
Permitted Storage Volume, ft3:
Minimum Required Volume, ft3:
Receiving Stream/River Basin:
Stream Index Number:
Classification of Water Body:
II. SCHEDULE OF COMPLIANCE
0.57
15,990
12
16.0
15.0
1,200
2,755
2,597
UT to Broad Creek, Tar Pamlico
29-10-(1)
"C, NSW"
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. Drainage features, such as vegetated buffers and grassed swales that provide treatment
for the low -density areas and as shown on the approved plans as part of the stormwater
management system, shall NOT be filled in, altered, or piped without submitting a
revision to the permit and receiving approval from the Division.
4. The permittee is responsible for verifying that the proposed built -upon area for the entire
lot does not exceed the maximum allowed by this permit.
3. The permittee shall at all times provide the operation and maintenance necessary to
assure the permitted stormwater system functions at optimum efficiency. The approved
Operation and Maintenance Plans 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 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, filter media, flow spreader,
catch basins, piping and vegetated filter.
g. A clear access path to the bypass structure must be available at all times.
4. Records of maintenance activities must be kept and made available upon request to
authorized personnel of DEMLR. The records will indicate the date, activity, name of
person performing the work and what actions were taken.
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State Stormwater Management Systems
Permit No. SW7050414 Modification
5. 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.
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. The stormwater systems shall not be used as Erosion Control devices. They must be
kept off line and free from sediment until the project is complete and the entire site has
been stabilized.
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
development, 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.
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 DEMLR, 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.
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State Stormwater Management Systems
Permit No. SW7050414 Modification
2. Failure to abide by the conditions and limitations contained in this permit may subject the
Permittee to enforcement action by the DEMLR, 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 DEQ 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 nd day of January 2019.
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
Danny Smith, Interim Director
Division of Energy, Mineral, and Land Resources
By Authority of the Environmental Management Commission
Permit No. SW7050414 Modification
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State Stormwater Management Systems
Permit No. SW7050414 Modification
State Stormwater Permit No SW7050414 - MODIFICATION
Washington Montessori School
Beaufort County
Designer's Certification
I, , as a duly registered in the
State of North Carolina, having been authorized to observe (periodically/ weekly/ full time) the
construction of the project,
(Project)
for
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.
Signature
Registration Number
Date
SEAL
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State Stormwater Management Systems
Permit No. SW7050414 Modification
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 bypass structure elevations are per the approved plan.
6. The bypass structure is located per the approved plans.
7. A 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. All required design depths are provided.
13. All required parts of the system are provided.
14. The required system dimensions are provided per the approved plans.
Noted deviations from approved plans & specifications:
cc: DEQ —Washington Regional Office