SW8970104_Historical File_20000110

January 10, 2000
Mr. Chris Stephens, President
Landmark Developers, Inc.
PO Box 4127
Wilmington, NC 28406
ry di n
°� CL,( Y\Ot iri
i�A
Subject: Permit No. SW8 970104 Modification
Magnolia Greens Master Plan
High Density Subdivision Stormwater Project
Brunswick County
Dear Mr. Stephens:
The Wilmington Regional Office received a complete modification to the Stormwater Management Permit Application
for Magnolia Greens Master Plan on January 4, 2000. 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 211.1000. We are
forwarding Permit No. SW8 970104 Modification, dated January 10, 2000, for the construction of the project,
Magnolia Greens Master Plan.
This permit shall be effective from the date of issuance until October 4, 2009, 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 Linda Lewis, or me at
[phone].
Sincerely,
Rick Shiver
Water Quality Regional Supervisor
RSS/:arl S:\WQS\STORMWAT\PERMIT\970104.JAN
cc: Davis Fennell, P.E.
Delaney Aycock, Brunswick County Inspections
Linda. Lewis
Wilmington Regional Office
Central Files

State Stormwater Management Systems
Permit No. SW8 970104 Modification
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
Landmark Developers, Inc.
Magnolia Greens Master Plan
Brunswick County
FOR THE
construction, operation and maintenance of 2 wet detention ponds and a low density subdivision with a curb
outlet system 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 modified permit shall be effective from the date of issuance until October 4, 2009 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. Stormwater Management measures are 2 wet detention ponds
and a curb outlet system for the low density portions of the project.
2. This stormwater system has been approved for the management of stormwater runoff as described on
page 3 of this permit, the Project Data Sheet. The subdivision is permitted for a total of 1019 lots. The
built -upon area permitted to date is: 249 single family lots @4,000 ft2 each (Sections 1-9); Tract A
(Sections 11 & 12) with 76 lots @3,500 ft2 each; the Clubhouse @3.96 acres; Tract N (Section 8) is
permitted for 21 lots @4,000 ft2; and 67 lots @4,000 ftz for the Patio Homes I site (Tract D). Tracts
E and O (Sections 8, 9, and 10) are permitted under SW8 981008 for 99 lots @4,000 ft2 and a
detention pond; and the West Commercial Area is permitted under SW8 980807 for 3.93 acres of
built -upon area. Future development includes the East Commercial Area @6.37 acres; 552
Multi -family units @1,200 ft2 each (Tracts K, L, M, P & Q); 507 single family lots @4,000 ft2
(Tracts B, C &D);
IN

State Stormwater Management Systems
Permit No. SW8 970104 Modification
3. Approved plans and specifications for this project are incorporated by reference and are enforceable
parts of the permit.
DIVISION OF WATER QUALITY
PROJECT DATA SHEET
Project Name: Magnolia Greens
Permit Number: SW8 970104 Modification
Location: Brunswick County
Applicant: Mr. Chris Stephens, President
Mailing Address: Landmark Developers, Inc.
PO Box 4127
Wilmington, NC 28406
Application Date: January 4, 2000 (Modification complete)
Receiving Stream/Classification: Jackey's Creek (CFR 18-77-3)
Sturgeon Creek (CFR18-77-1)
Classification of Water Body:
Drainage Area, acres:
Pond Depth, feet:
Permanent Pool Elevation, FMSL:
Total Impervious Surfaces, ft2:
Lot BUA, ft2:
Roads/Parking, ft2
Sidewalk, ft2
Patio Homes I, ft2:
Maintenance Building
Offsite Area entering Pond, ft2:
Required Surface Area, ft2:
Provided Surface.Area, ft2:
Required Storage Volume, ft3:
Provided Storage Volume, ft3:
"C Sw"
POND 1 POND 5
141.6 26.2
7 7.5
18
17
1,688,086
366,850
845,084
209,299
453,938
119,920
121,100
28,919
268,000
------
8,712
none, per Engineer
64,602 9,864
82,200 11,137
152,307 32,269
183,796 32,334
3

State Stormwater Management Systems
Permit No. SW8 970104 Modification
Temporary Storage Elevation, FMSL: 20.1 19.4
Controlling Orifice: 2 each @4"_ 2"_ pipe
II. SCHEDULE OF COMPLIANCE
1. No homeowner/lot owner/developer shall fill in, alter, or pipe any drainage feature (such as swales or
curb outlet swales) shown on the approved plans as part of the stormwater management system
without submitting a revision to the permit and receiving approval from the Division prior to
construction.
2. The permittee is responsible for verifying that the proposed built -upon area does not exceed the
allowable built -upon area. Once the lot transfer is complete, the built -upon area may not be revised
without approval from the Division of Water Quality, and responsibility for meeting the built -upon
area limit is transferred to the individual property owner.
3. The uncollected portions of the low density subdivision are served by a Curb Outlet System. The
swales are generally located between lots, and must be maintained with a stable, vegetated 5:1
sideslope, be a minimum of 100' long, have a longitudinal slope of 5% or less, maintain a dense,
vegetated cover, and be able to carry the peak flow from a 10 year storm in a non -erosive manner.
4. The following items will require a modification to the permit:
a. Any revision to the approved plans, regardless of size.
b. Project name change.
C. Transfer of ownership.
d. Redesign or addition to the approved amount of built -upon area.
e. Further subdivision of the project area.
f. Filling in, altering, or piping of any vegetative conveyance shown on the approved plan.
5. The Director may determine that other revisions to the project should require a modification to the
permit.
6. The Director may notify the pern ittee 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.
7. The stormwater management system (ponds and curb outlet swale system) shall be constructed in
their entirety, vegetated and operational for their intended use prior to the construction of any
built -upon surface.
During construction, erosion shall be kept to a minimum and any eroded areas of the system will be
repaired immediately.
9. Upon completion of construction, prior to issuance of a Certificate of Occupancy, and prior to
operation of this permitted facility, a certification must be received from an appropriate designer for
the system installed certifying that the permitted facility has been installed in accordance with this
permit, the approved plans and specifications, and other supporting documentation. Any deviations
from the approved plans and specifications must be noted on the Certification.

State Stormwater Management Systems
Permit No. SW8 970104 Modification
10. Decorative spray fountains will not be allowed in the stormwater treatment system.
11. 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.
12. Prior to transfer of ownership from the permittee to a third party such as an HOA, the stormwater
management systems must be inspected by DWQ personnel, and determined to be in compliance with
all permit conditions. Records of maintenance activities will be required.
13. 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. Mowing and revegetation of side slopes of the pond and the swales.
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.
14. 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.
15. Prior to the sale of any lot, deed restrictions must be recorded which limit the built -upon area per lot
to the amount as shown on the Project Data Sheet, per Section I, Part 2. The recorded statements must
follow the form:
a. "The maximum built -upon area per lot in this section is *see below square feet. This allotted
amount includes any built -upon area constructed within the lot property boundaries, and that
portion of the right-of-way between the front lot line and the edge of the pavement. Built upon
area includes, but is not limited to, structures, asphalt, concrete, gravel, brick, stone, slate, and
coquina, but does not include raised, open wood decking, or the water surface of swimming
Pools."
b. "The covenants pertaining to stormwater regulations may not be changed or deleted without
concurrence of the State."
C. "Alteration of the drainage as shown on the approved plan, including the curb outlet swales,
may not take place without the concurrence of the State."
d. "Lots within CAMA's Area of Environmental Concern may be subject to a reduction in their
allowable built -upon area due to LAMA regulations."
e. "Each lot shall maintain a minimum of 30' of vegetated buffer between any impervious
surface on the lot and surface waters."
* The permittee will fill in the built -upon area associated with each lot in the section, per the
57

State Stormwater Management Systems
Permit No. SW8 970104 Modification
requirements of Section I, Part 2 this permit.
16. A copy of the recorded deed restrictions must be submitted to the Division within 30 days of the date
of recording the plat, and prior to selling lots. The recorded copy must bear the signature of the
Permittee, the deed book number and page, and stamp/signature of the Register of Deeds.
17. 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.
18. 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.
19. All runoff from the impervious surfaces of the clubhouse area, including parking lots, roads, and
building, must drain into the "Golf Pond" permitted under SW8 990628. Pond #3, as shown on the
Master Plan, is no longer a stormwater treatment pond.
III. GENERAL CONDITIONS
1. This permit is not transferable. In the event there is a desire for the facilities to change ownership, or
there is a name change of the Permittee, a "Name/Ownership Change Form" must be submitted to the
Division of Water Quality accompanied by appropriate documentation from the parties involved,
such as a. copy of the deed of trust. Other supporting materials, such as a signed Operation and
Maintenance plan in the case of engineered systems, will also be required. The project must be in
good standing with DWQ. The approval of this request will be considered on its merits and may or
may not be approved.
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) which have 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 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.
6. Permittee grants permission to staff of the DWQ to access the property for the purposes of inspecting
the stormwater facilities during normal business hours.
7. The approved plan set consists of tke October 15, 1ggq, revised Master Plan, Patio Home i site
plan witk Pond 1 details, Pond 5 detail sheet, and the Clubhouse Site Plan. The permittee will
swap out the required plans and replace outdated streets with tke revised ones.
Permit issued tkis tke 1Otk day of January, 2000.
0

State Stormwater Management Systems
Permit No. SW8 970104 Modification
NORTH CAROLiNA ENVIRONMENTAL MANAGEMENT COMMISSION
Kerr T . Stevens, Director
Division of Water Quality
By Authority of the Environmental Management Commission
Permit Number SW8 4709.04 Modification
Magnolia Greens Master Plan Page I. of
z
Stormwater Permit No. SW8 970104 Modification
Brunswick County
Designer's Certification
I, . as a duly registered in the State of
North Carolina, having been authorized to observe (periodically/weekly/full time) the construction of
the project,
_(Project)
for (Project Owner) hereby state that, to the best of my abilities, due
care and diligence was used in the observation of the project construction such that the construction
was observed to be built within substantial compliance and intent of the approved plans and
specifications.
T ►ne checklist of items on page z of this form are a part of this Certification.
Noted deviations from approved plans and specifications:
Signature
Registration Number .
Date
SEAL
7

State Stormwater Management Systems
Permit No. SW8 970104 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.
Page 2 of 2
3.All the built -upon area associated with the project is graded such that the runoff drains to the system.
4.The outlet/bypass structure elevations are per the approved plan.
5.The outlet structure is located per the approved plans.
6.Trash rack is provided on the outlet/bypass structure.
7.All slopes are grassed with permanent vegetation.
8.Vegetated slopes are no steeper than 3:1.
9. i he inlets are located per the approved plans and do not cause short-circuiting of the system.
10. The permitted amounts of surface area and/or volume have been provided.
11. Required drawdown devices are correctly sized per the approved plans.
12. All required design depths are provided.
_13. All required parts of the system are provided, such as a vegetated shelf, a forebay, and the vegetated
filter.
14. The overall dimensions of the system, as shown on the approved plans, are provided.
cc: NCDr'NR-D�+` Q Regional Office
Delaney Aycock, Brunswick County Building Inspector

Permit No. Diu 3 g170 /G¢f1C?p
(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
DWO Storm water 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: Magnolia Greens Plantation
Contact Person: Ghr15 Stephens Phone Number: [phone]
For project with multiple basins, specify which basin this worksheet applies to: Fond# I
elevations
Basin Bottom Elevation
Permanent Pool Elevation
Temporary Pool Elevation
areas
Permanent Pool Surface Area
Drainage Area
Impervious Area
volumes
Permanent Pool Volume
Temporary Pool Volume
Forebay Volume
Other parameters
SA/DA'
Diameter of Orifice
Design Rainfall
Design TSS Removal 2
1 1 .0
ft.
18.0
ft.
20.1
ft.
82,200
sq. ft.
151.3
ac.
40.58
ac.
403,29G
cu. ft.
183,975
cu. ft.
G7,579
cu. ft.
1.0438
2 4
in.
I
In.
90
%
(floor of the basin)
(elevation of the or f ce)
(elevation of the discharge structure overflow)
(water surface area at the orifice elevation)
(on -site and off -site drainage to the basin)
(on -site and off-siie drainage to the basin)
(combined volume of main basin and forebay)
(volume detained above the permanent pool)
(approximately 20% of total volume)
(surface area to drainage area ratio from DWQ table)
(2 to S day temporary pool draw -down required)
(minimum U1150% required)
Form: SWU-102 Rev 3.99 Page 1 of 4

Footnotes:
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 BhV manual provides design tables for both 85% TSS removal and 90% TSS removal.
H. 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.
ds:
a.
b.
C.
d.
e.
f.
9.
h.
i.
J
k.
The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
The forebay volume is approximately equal to 20% of the basin volume.
The temporary pool controls runoff from the design storm event.
The temporary pool draws down in 2 to 5 days.
If required, a 30-foot vegetative filter is provided at the outlet ( include non -erosive flow
calculations)
The basin length to width ratio is greater than 3:1.
The basin side slopes above the permanent pool are no steeper than 3:1.
A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
Vegetative cover above the permanent pool elevation is specified.
A trash rack or similar device is provided for both the overflow and orifice.
A recorded drainage easement is provided for each basin including access to nearest right -
of —way.
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.
Yr''F r4.w?.JM?
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 does3no
incorporate a vegetated filter at the outlet.
This system (check one) 0 does doesincorporate pretreatment other than a forebay.
Maintenance activities shall be performed as follows:
Form: SWU-102 Rev 3.99 Page 2 of 4

1. 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 as such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 5.25 feet in the main pond, the sediment shall be removed.
When the permanent pool depth reads 3.00 feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation = 1$, 0
Sediment Removal El anon = 15.0 75°k Sediment Removal Elevation — 12.25 75% '
Bottom Elevation 14.0 25% Bottom Elevation = 1 1.0 25%
fil
FORFBAY 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.
7. All components of the wet detention basin system shall be maintained in good working order.
Form: SWU-102 Rev 3.99 Page 3 of 4

I a;,Imowledge 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: W. Christopher Stephens
Title:
Addre.
Phone
Signat
Date:
Pro��.lor�
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been
sold and a resident of the subdivision has been named the president.
,a Notary Public for the State of
County of GaT/ QED ✓.V ,do hereby certify that ( G /W,14Wy
personally appeared before me -I-Xz1f day of Ocf l'y 999 ,and acknowledge the
this of due
execution of the foregoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires 0? ^ 0— )-010
Form: SVM-102 Rev 3.99 Page 4 of 4

a
an-04-00 02:36P Cape Fear Engineering
P.01
Fax Tmimfift9
To: Linda Lewis
From: K Davis Fennell
Re: Patio Homes I at Magnolia Greens
SW Project No. sw8 991010
Date: 01/04/00
4WCAPE FEAR
Engineering, Inc.
5040 New Centre ©rive, Suite f)
Wilmington, N.C. 28403
Voice [phone]
Fax [phone]
E-mall cfeCa7bellsouth.net
Fax: [phone]
CC:
Pages: 3
Job #: 230-16
IF YOU DO NOT RECEIVE THIS DOCUMENT CLEARLY, PLEASE CALL [phone]
IM This is your original copy ❑ Original Copy tD be mailed
NOTES:
1

Jan-04-00 02:36P Cape Fear Engineering
!'
P_02
CAPE FEAR
Engineering, Inc.
5040 Nov Centres M.., Suite D MmIngton, NC 28405
TEL
(MO) 790-858" AM (MO) ?W-M&S
0e06e1160uth.net
January 4, 2000
Linda Lewis
NCDENP,
Water Quality
127 Cardinal Drive Ext.
Wilmington, NC 28403
Re: Patio Homes I at Magnolia Greens
5W Project No. 5W8 991010
Dear Ms. Lewis:
This letter is an attempt to summarize the history of the stormwater treatment
facilities at Magnolia Greens (particularly Pond# 1) and the proposed development
Patio Homes I. 1 hope that we can clarify the intent of the project so that we
may move forward in the permitting process.
Magnolia Greens Golf Plantation was originally permitted as a mix of high and low
density development. The master plan, covered under permit 5W8 970104,
included development proposed for immediate construction and also projected
the impervious coverage for future projects. The master plan, permit
applications, and appropriate supplements were constructed, submitted, revised
and resubmitted at the direction and assistance of regional staff in the Division of
Water Quality.
Pond # I , a stormwater detention and treatment facility, was proposed and
permitted for immediate construction, but was largely oversized. The purpose for
over5l21nq the pond was to allow for future development within the permitted
drainage area without having to reconstruct the stormwater pond each time a new
project were to be proposed. Again, this permitting strategy %Ajar devised at the
direction and a5515tance of DWQ regional staff.
The Patio Home I development is precisely the type of project the master plan
and permit were devised to accommodate. This project, originally submitted on
November 1, 1999, proposed to modify the master plan and permit (5W8
9701 04) to increase the impervious coverage within the permitted drainage area
of Pond # 1 by constructing the Patio Homes I development. I stress that th15
development lies completely within the drainage area as shown on the permitted
master plan, last approved on October 4, 1999.

Jan-04-00 02:37P Cape Fear Engineering
P.03
The November 1, 1599 submittal included a revised permit application requesting
modification to 5W8 970104, a revised low density supplement including all of
Magnolia Greens (including those projects permitted as "stand alone"
developments), and a revised wet detention basin supplement for Pond# I . Also
included were copies of the revised master plan (showing the patio Home I area)
and a site specific stormwater plan for Patio Homes I at a larger scale to assist in
the review process.
In our recent telephone conversations, you have stated that all of this information
is technically correct and in compliance. The only outstanding issue is the
logistics of modifying the existing permit to include Patio Homes I versus
permitting the project as a stand alone development with an off -site treatment
facility (Pond# I ).
To permit Patio Homes I as a stand alone development with an off -site treatment
facility would require that all of the plans, applications, and supporting documents
be revised at the expense of the developer, both monetarily and, more
importantly, in time delays. The documents that you have under review are
compliant with regulations and under the permitting strategy devised by DWO
(the strategy of master planning), quite permutable without the costly rev15+on5
to plans, applications, etc.
It is my hope that we can modify 5W8 970104 with the documents currently
under review and that any future developments at Magnolia Greens be permitted
as separate, stand alone projects.
I trust. this information to be sufficient for your review. I look forward to
discussing this issue with you further at your earliest convenience.
51ncerely,
K. Davis Fennell, PE
Cc: file (230-1 G "30")
Chris Stephens, Landmark

Stormwater
Design Narrative and Calculations
For
The Patio Homes I
at
Magnolia Greens Plantation
Brunswick County, North Carolina
STORMWATER
E C E I V E
Prepared for � D
NOV 011999
Landmark Developers, Inc.
5022 Wrightsville Ave. Suite 102 rigoj HC)i
Wilmington, North Carolina 28403
[phone]
Date: October 1999
SEAL.
024908
:.NGINE��ol,
Prepared by
Cape Fear Engineering, Inc.
5040 New Centre Dr., Suite D
Wilmington, North Carolina 28403
[phone]

DESIGN NARRATIVE
L GENERAL:
The project site is located along the northeast right-of-way on NC Hwy 17, within Brunswick
County, North Carolina. The project area consists of approximately 16 acres within the Magnolia
Greens Plantation subdivision, all of which will be disturbed. The subdivision entrance is
approximately 1000 feet northeast from the intersection of Hwy 17 and Lanvale road. This
development is located near the intersection of Grandiflora Drive and Lanvale Road. Drainage
considerations are to be in accordance with DEM stormwater requirements.
The intent of this project is to develop a single family patio home community. This project will
also include the installation of roads, utilities, a sub -surface stormwater drainage system that will
connect to existing piping within the community.
2. EXISTING SITE:
Site topography in the area is relatively flat with slopes typically less than one (1) percent. There
is existing storm drain piping that will be utilized to convey runoff from this project to an
existing wet detention pond.
Vegetation consists primarily of grasses and minor ground cover within the area of the
improvements. Subsurface soils are typically a mixture of sand with a few clayey areas.
3. PROPOSED IMPROVEMENTS:
Improvements proposed to serve the patio home community include the construction of roads,
utilities, and a sub -surface stormwater drainage system. Pond #1, and existing, pc-1 itted wet
detention pond will be utilized for treatment of stormwater runoff. Two amenity ponds are also
proposed for the site.
4. DRAINAGE CALCULATION CONSIDERATIONS:
Drainage on the site will sheet flow to curb inlets within roadway areas. Proposed roads are to
be cut 1 to 1.5 feet below existing grade to insure that the property will drain to the street. Any
roof drains or gutters from buildings will drain to the collection system. From there, the drainage
will be piped to a wet detention pond in accordance with NCDENR Stormwater regulations.
5. EROSION CONTROL CONSIDERATIONS:
The existing wet detention pond will provide ample sediment storage for the disturbed area and
will be utilized as a temporary sediment basin during construction. Inlet protection is to be
installed as the curb inlets of the drainage piping system are constructed to minimize this amount
of sediment entering the collection system and, ultimately, the temporary sediment basin.

Page Two
Design Narrative
Patio Homes I
Erosion Control Measures and Sequence:
a. Temporary construction entrance.
b. Temporary sediment basin (wet detention pond).
c. Energy dissipaters at the pipes into and out of the detention pond.
d. Temporary inlet sediment protection at storm drain inlets.
e. Temporary seeding should construction be halted for the specified time limit (refer to
specifications)
f. Remove all temporary erosion control measures once installation of utilities and paving
have been completed and a good vegetative ground cover has been established.
6. MAINTENANCE CONSIDERATIONS:
During construction, the Contractor shall be required to inspect and repair as needed all erosion
control devices after any significant rain event. Any measure found not performing its intended
function should be repaired immediately. Upon completion of construction and establishment of
permanent ground cover, the Owner shall be responsible for maintenance on the project site.

WET POND DATA SHEET
PATIO I AT MAGNOLIA GREENS
POND#I
DRAINAGE AREA (Ad) =
IMPERVIOUS AREA (Ai):
BUILDINGS:
ROADS:
PARKING:
SIDEWALKS:
TOTAL:
PERCENT IMPERVIOUS (1):
I = Ad/Ai = 27.37%
141 . G ACRES
25.55 ACRES
10.42 ACRES
0.00 ACRES
2.78 ACRES
38.75 ACRES
POND# I SHALL BE 7' DEEP AND DESIGNED TO REMOVE 90% T55.
SA/DA= 1.0474%
REQUIRED SURFACE AREA AT PERMANENT POOL:
SAREQ.= 1 .4831 184 AC. = G4GO4.G4 SF
SURFACE AREA PROVIDED AT PERMANENT POOL (EL. 18)= 82200 SF
.................... .......... ............................................................................ ...............
.
SA PROV'D= 82200 > G4GO4.G4 =SA KEW OK
..........................................................................................................................:
MINIMUM REQUIRED VOLUME (SIMPLE METHOD BY TOM SCHUELER):
Rv=0.05+0.009*(I)
Rv= 0.29G2924
VOLUME= I "*Rv*Ad = 3.49G25 AC -FT
152297 PT^3
VOLUME PROVIDED AT TEMPORARY POOL:
Lim
Ib
62200
19
87223
20
92299
21
97754
INCREM. TOTAL
u 0
84712 84712
897G1 174473
95027 2G9499
POND# I DATA 5HEET
PAGE I OF 3
OCTOBER, 1999

5ET TEMP. POOL ELEVATION:
REQ'D EL.= 19.75294G *-SAY 20.1 (AS -BUILT RIM EL.)
VOL. PROV'D = 183975. 15 CF
........................................................................................................................
VOL. PROV'D= 153975. 15 > 15229G.7 =VOL. REQ'D OK
............... ................................................................................................... ........
:
FOREBAY SIZING:
PERMANENT POOL VOLUME:
INCREM.
TOTAL
EL.
SA (5-0
VOL. (CF)
fj
II
37079
0
0
12
39751
38415
38415
13
42481
4111G
79531
14
58384
50432.5
1299G3.5
15
G2953
GOGG8.5
19OG32
I G
G7G44
G5298.5
255930.5
*-MIN. SURFACE AREA
17
72444
70044
325974.5
USE THIS VOLUME
18
82200
77322
40329G.5
TO SIZE FOREBAY.
REQ'D VOLUME = 20% TOTAL =
51 18G
CF
*-(20% TOTAL = (50000 CF)
CHECK FOREBAY VOLUME:
INCREM. TOTAL
Ej.
SA (5F)
VOL, (Cf) VOL, ( F)
14
1311G
0 0
15
14837
13077 13977
IG
IGG24
15731 29707
17
184GO
17542 47249
18
22200
20330 G7579
PROV'D VOLUME =
•......................................................................................................................•
G7579
CP (4' DEEP FOREBAY)
MAX. VOL.
...........................................................................................................................
(800G0) > PROV'D VOL. (1-07579) > MIN. VOL. (51 18G)
*POREBAY MEETS DESIGN CRITERIA
POND# I DATA 5HEET
PAGE 2 OF 3
OCTOBER, 1990

ORIFICE 51ZING: REQ'D DRAWDOWN TIME = 2-5 DAYS
Q2= 0.88134G4 CF5 (FOR 2 DAY DRAWDOWN)
Q5= 0.3525385 CF5 (FOR 5 DAY DRAWDOWN)
SELECT 2 x 4" CIRCULAR ORIFICE, EL. 18' (PERM. POOL EL.)
Q PROV'D= 2*(Cd*A`(2gh) ^ 1 /2)
Q PROV'D= 0.82G385 1
WHERE: Cd= O.G
A= 0.08727 SF
g = 3 2.2 FP5/5
h= AVE. HEAD =(2. P-27 1 2)/2
0.9G7
....................................................................
Q2> 0.82G3851 >Q5 OK
......................................................................
DRAWDOWN TIME:
TIME - VOLUME = 2.13302 DAYS
Q PROV'D
POND# I DATA SHEET
PAGE 3 OF 3
OCTOBER, 1999

c c
sc
r0
ooi
lT
�0
w L �'
O
LO
O
(O
r
ti
CO
L00
O
O
r
00
Z
N
N
N
N
N
N
N
N
N
N
N
11.1
Q
to
Q
0` (j
O
O
O
O
O
O
O
4)
O
O
O
Z
J 0 J
V .�.
O
C
O
O
C
C
r
C
r
C
r
O
0
C
- N
n
a
a
a
n
a
a
c
m
C
O
M
M
M
M
M
M
M
M
W
m
Z>
_M
O
O
O
O
O
O
O
O
_M
O
_M
O
O
z_
J
O
LL
O
H
> >-�
�
00
rn
—
M
CD M
O
a0
o
O
o
O
O
o
o
W
N
C W
C
N
C
N
r
N
N
4
L6
Ln
c+1
r
07
CD
6
r..
6
m
�
N
N
N
N
N
N
N
N
0)
Z
N
ID
�
O
n
O
OD
O
W
N
f0
O
tt
O
O
O
co
O
O)
O
O
O
O
O
O
F¢-
Q
_ _
W
N
N
N
N
N
N
N
N
N
N
N
Q
~
O
c
II
3
ti
Y
Z
d m c
d
c
M V
O
O
O
O
O
to
LO
O
LO
LO
toC
O
c C�
to
Lq
O
o
O
. o
to
LO
O
o
co
LO
w
LO
co
LO
Lo
LO
Co
U")
(o
LO
II
0
U
C d V
LM
O
O
O
O
CD
N
NLO
_c
LL
c
d
�
C O a
N
CO
O
co
O
co
00
N
st
lb
r
N
O
N
Q
3 H
C
7�
C
r
C
C
cl
C
C
r
C
O
U
Z
11
[r
m
O
c a
0
m
m
�a
m
_m
m
`m
m
7
7
7
'
�
7
7
7
7
J
U
U
U
U
U
U
U
U
U
U
U
LL
LL
d
- -
o
r
C C
J N :r
co
co
CD
C)
N
co
co
co
Go00
coII
N
N
co
I
Im
O .
d
C C
O
M
a
_
J m 904
N
M
N
<
N
N
Pam)
N
N
co
Lo
N
X
Lp
C W
M
LOco
0
CD
O
cn
pOp
aNO
N
4
G Co .�
II
Cr
G
CO
d'
LO
co
c!
00
Lo
r0
o
LU
a
om
000)
J
U
m
U
U
U
U
U
Uo
W
O
J
m
m
m
LL
O
Z
m
W
-)
C7
c
co
J
r
N
Cl)v
LO
co
n
co
rn
r
d
in

O
r
N
m
tt
to
CO
ItOD
Cn
o
rn
0
r
V C
d 3
C O
0
1-
tO
OD
O
0)
N
co
O
't
O
O
O
co
O
m
O
O
O
u )
O
c0
Ob
r
'O v
N
N
N
N
N
N
N
N
N
N
N
OT
r
> 7'
CC)
OD
- O
Q)
N
r
O
c0
CA
0)
O
00
O
0)
O
O
O
O
CO
O
h
W
..
C
o
N
O
N
N
r
N
N
N
N
N
N
N
COS!
Z
N
CD
co
CA
CD
co
O
CD
N
O
O
C)o
O
�NNNN
_ •O ...
N
NNNti
N
N
N
'
CL
00)
LOi•
LO
COD
0)
.=
M
o
N
a
T
r
7
N
NNNNNNN
N
N
W
Z
C:
0 3 W
m
4
m
CD
m
h
O
O
N
T
0I
Cn
LL
O
.� .0
C7
Ci
to
.4
4
CV
it
W
m
_
U N
O O.
M
to
CD
M
N
CD
Cl
N
r
n
lC)
'V
CM
CM
ui
CC)
d'
C`i
V
N
'i
CV
Z
J
H
d
0
C O.
co
r
o
r
^
O
co
00
N
It
a0
CO
N
m
r
t
o
o
O
r
o
O
o
O
o
0
LD
d �
C C
N
CD
Cn
cM04
�
O
M
N
N
N
Cl)N
N
Ico t
LO
N
r
Iapl
C
C
U
U
U
U
U
U
U
U
U
U
U
'C
N K
'r e
to
M
co
cp
to
M.
O
Cl)
N
a0
ao
ao
a0
a0
0o
d
E
a_
ld y
v
' r
co
O
st
O'r''�•
Cl)N
N
m
Cn
m
1C7
m
V
N
N
CA
Co
Co
V
� 3
m
o
to
r
1.
r
,�
H s~ol
N
N
N
N
4
O
Co
q
ti
CO
C7
th
o
O
s}
co
LL
O
�
Q r....
o
0
0
0
O
c
0
0
0
0
o
O
O
C
Z
0
O
LQ
O
+R,
tD
O
CD
r
co
n
m
N
F- V
C
N
N
ate-
CO
e}
it
Cl)
o
'V
ll.l
+
J
U
L
w N s
CO
O
CD
m
01
0)
Cn
r
M
N
't
N
0
N
Cl
t
OC C :.
to
CO
0
to
n
T
r-
N
1`
I,-h
N
r
n
N
n
0
L
DCD
C
!
N
F2 'E
O
0
O
N
Co
r
O
st
C.
N
O
M
0
r.:
CD
0
ui
CD
Cn
CC)
0
0
6
r
7 Q
CA
lt)
Nt
N
I�
O
W
co
m
Ch
O
O
In
O
N
CO
I
w
.N
N
C
C1 Q
C Ci
CD
ao
O
O
O
O
LO
coCD
C.
O
n
N
Cl)
CO
Cl)O
tt)
LO
co
uO
N
CD
:C 6
�
Co
In
O
O
O
O
CO
�
O
O
0
In
In
0
0
In
CO
tD
0
co
CC)
0
II
� V
O
O
O
O
O
O
O
O
O
O
O
a
V y v I
LO
O
O
O
O
CD
O
CA
N
v
O
to
T v
�"
j�Qp
U
L
r
O
d'
r
Q)
m
0
r
•CD �
W
u
m
a*
m
mN
co
co
Cl)
2
Vc6pp
J
V
U
m
LU
J#
r'
N
co
sl'
CD
CD
h
no
O
w
Z

rA
.,.y
WD
F.4
rn
rn
0
0
cn
U
U-
ri
H
3
z

�
IL
it
0
�
�
�
�
0
�
�
�
�
LM
�
�
cn
E
L
0
-W
co
make
R
§
2
MM
Cl) n
§
§
z
§ § .
§
A
•
�t-1
%
ZD
-
w
483
/a
t t
\»
o o
i
a
a
n co
w
$
z§
>
§ G
j
7
\CL
6
>'E
Cl 2
—�
Q q
co\
R
&
z
2
k
> F
r
S Mu
q §
/
R
/
k
C.
R
z
�(D2
'E
u-) L
a
«
kk-
q $
It
■©
§
3
.
E
§
§
§
�
§��
$ g
b
e d
)
.
& to_)
_\
W0
CIL
g e
E
..
a
\
..0—
—
04
:3
00 Go
;
k
• �
E
am
§2
aE §
\
2
0 —M
§ —
k§3
'
04
.
_
§|
§ƒ■|
o �
\
�
/
§
Q
z
■
§Os
u
w
_n
co ^
§
O
{
g
z
L:-3
~
\
§
'

�
a
a
.2
�
�
�
�
m
F-
LM
�
�
CD
co
E
�
0
4-1
cn
kcE
k r-
k
_-0-
§
q g
>gE
^ vi
j
=
q §
z
�
009
§ §
_"-
CN 04
-i
C*4
z�£
g §
§
0k
U.
2 \
0
�
k
\0
2
z
CN
/
§�7
a g
�.�
a e
2g£
/
�
f #
�
CN
i
CDap
/ }
CL
�2=
§
C� ®
%
2
■�
�2£
R
a )
i
§
«tea
d
z
/
8
o
=
2
)0
_
/
E
00
§
- ®
2
+
LL
t7.
■ 3�
00 a
§
j
m
0
£
3 /
§
<
co §
�
:
/
k�
$ G
o d
0CD
Lq L
\
•
■�
0 C
_
)Jm
§ Q
«S
L
"
g
_2_
t
04 C)
§
2
k B
=
i
©
E
~
/
§

11,
N
A
M
.�w
Qn
�1
rn
a
cz
i
C)
1
r/
5-

m
a
�t
0
�
�
�
0
�
�
�
�
�
LM
�
�
�
co
E
L
O
'4.j
cn
c = ■
o
04
�
«
«
2
o
c
o
0
0
0
0
2
04
04
\
\
§
\
\
�
.
o
§■ E
e
LO
®=
n
R
R
z
2
4�3
o
d
d
d
a_
Z)
j k
c
�
§
�
M
n
m
m
co
Cl)
w
;
q
§
&
§
q
%
§
§
\
§
/
k- F
0
co
H�
2
8 •
w
2
I w
§
k&§§
Q
q
j
z
g
\§ F_
8
G
k
2
co
p
§
/
/
k
§
§
�
§
§
e
co
&
c
d
d
d
d
a
d
a)d
a)
p
'
/
If)
o
0
e
LO
n
L
�
0/
q)
7
g
7
7
7
k
E R£
r
8
q%
g@§
o. 3
d
0
§
/
. E
moo—
o
o
a
F-
n
§
q
z
0 CDE
$
2
#
§
Cl)
Q
O§
Q
O§
Q
k
»
—
e
§] r
CD
co{
e
E� 4 2
k
m
&
,s
a.
§) E
o/§
G\
r
g
k
I
2 C
§
E
2
M
f
f§
/
Cc
|
$
§
f
1-0
"
/
6 I
(
to
V.-
CD
«
Cla.
tcn
2
o
a
§
Q
Q
Q
■
C14/
4
m
6
W
w
§
k
\
§
d
k
UL
°
§
k
w
Q
©
n
n
c
\
\

W)
l0
-
IT
c
>oV
o
co
v
— •0
0
o
N
0
r
N
N
N
N
N
r
a
O
O
co
W
QN
c00
N
�
OR
a00
C
CC)
r
O
N
nl
N
CV
N
Cl)
N
m
N
C1I
N
Q
I Z
0
o
o
Lc)
C)
00�
S V
N N N N N N N
J
O
O
r
r
M
LO
M
CA
�
lRt
to
to
O
^
S 7
V
N
4
N
6
N
to
N
CO
N
6
N
CD
N
pj
W
Z
V c
° 3 in
O
M
N
co
00
to
to
O
J
LL
•O
to
C7
CV
r
CV
0
W
0 H
rLh
M
M
O
O
O
O
m
�
> >
O
N
to
C.)
CV
r
CV
Z
J
Cn
c O o
O
04
r
C*NJ
^
M
CV)
O
r
M
Q
H
-yin
o
0
0
0
0
0
0
C_ c
J d ...
O
N
I,-M
N
ti
M
r
N
OND
I1
C
C N •x
U
U
U
U
U
U
U
O
.0
J ' to C
N
^
m
N
N—
co
con.
E
CID
^
v
cO
rn
ci U"
0
N
n
A
CD
tri
a0+ 3 Y)
H v
to
CID
N
CO
CO
(D
r
C14
r-
CID
N
LL
0
_
.O
�
a��
o
n
o
0
0
0
o
U
z
In
.0.• O o
O
N
co
r
Lr
to
O C v
CID
co
CO
N
M
^
m
N
W
J
LL
V
Cw
OCID N N
n
C
M
COO
SD
O
N
N
0
to
i
CO
C
tO
d'
CO
N
O
O
O
N
�
CA
co
N.
W)
LO
U)
Cl)
r
O
W
V'
d'
CO
_
co
00
co
co
■�
y
N
CV
N
r
C7
O
O
CA
N
C
C Li
It C) CID LO N M CID
O
C
O
G
6
0
p
X
N V
CID
0
O
co
CID
tfOo
co
in
O
`Y
f0.) v
Co
C
C;
C)
0
C)
0
II
O
■
L
s m
O N O v co O
o o
r
r
o
o
r
_a
ID
LO
CO
^
c0
O
O
r,
F-
co
co
u
CO
c
�#
U
m
U
U
0
U
U
m`
�
J
N
CC)
o)
Ob
X
w
U
*
m
-
U
ii
U
�
U
*
U
LL
U
If
L
w
d
c_
C
vi
/$
J
r
N
Cl)
an
CO
I�
Z