HomeMy WebLinkAboutSW8070817_HISTORICAL FILE_20160812STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO
SW8 0_10 811
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
7-OW 08 12
YYYYMMDD
w
r
I S '4 ,✓
Energy Mineral&
Land Resources
ENVIRONMENTAL QUALITY
August 12, 2016
PAT McCRORY
Governor
DONALD R VAN DER VAART
Secretary
TRACY DAVIS
Director
Charles C Poindexter, II, Manger Robert Huth, Manager
Pelican Point CB, LLC Developer HDI Holdings, LLC, Property Owner
7923 Reunion Rd 5929 Market St
Wilmington, NC 28411 Wilmington, NC 28405-3615
Subject State Stormwater Management Permit No SW8 070817
Pelican Point
High Dcusity Infiltration Trench Project
New Hanover County
Dear Mr Poindexter and Mr Huth
The Wilmington Regional Office received a complete, modified State Stormwater Management Permit
Application for Pelican Point on August 12, 2016 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 modified Permit No SW8 070817 dated August 12, 2016, for
the construction, operation and maintenance of the BMP s and built -upon area associated with the subject
project
This permit shall be effective from the date of issuance until October 12, 2021, and shall be subject to the
conditions and limitations as specified therein Please pay special attention to the conditions listed in this
permit regarding the Operation and Maintenance of the BMP(s), recordation of deed restrictions,
certification of the BMP's, procedures for changing ownership, transferring the permit, and renewing the
permit Failure to establish an adequate system for operation and maintenance of the stormwater
management system, to record deed restrictions, to certify the BMP's to transfer the permit, or to renew
the permit, will result in future compliance problems As the identified developer of the project, Pelican
Point CB, LLC, shall be the designated permit holder and responsible for meeting the conditions and
limitations specified therein
The following modifications are included and covered by this permit
1 A revised site layout
2 The BMP has been re -designed and will be an infiltration trench
Please be aware that it is the responsibility of the permit holders, Pelican Point CB, LLC and HDI
Holdings, LLC, to notify the Division,of any changes in responsibility for complying with the permit and
request an ownership/name change for the stormwater permit However, please be reminded that if the
development agreement between Pelican Point CB, LLC and HDI Holdings, LLC is dissolved, cancelled
or defaults, and the Division is not notified by Pelican Point CB, LLC to transfer the permit, then the
responsibility for permit compliance reverts back to the property owner, HDI Holdings, LLC The
Division must be notified immediately of any permit ownership changes and submit a completed
Name/Ownership form to the Division within 30 days Otherwise Pelican Point CB, LLC and HDI
Holdings, LLC will be operating a stormwater treatment facility without a valid permit This is a
violation of NC General Statue 143-215 1 and may result in appropnate enforcement action including the
assessment of civil penalties of up to $25,000 per day
State of North Camlma I Environmental Quality I Energy himeral and Land Resources
Wilmington Regional Office 1127 Cardinal Dave Extension I Wilmington NC 28405
910 796 7215
State Stormwater Permit No SW8 070817
Page 2 of 2
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 OAH
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, or need additional information concerning this matter, please contact Christine
Hall in the Wilmington Regional Office at (910) 796-7215
Sincerely
31" Tracy Dads, P E , DirectiSr
Division of Energy, Mineral and Land Resources
GDS/canh %Stormwater\Permits & Prolects\2007\070817 HD\2016 08 permit 070817
cc Jim Honeycutt, Jr PE
New Hanover County Building Inspections
New Hanover County Engineering
Brian Stanberry, Town of Carolina Beach
Division of Coastal Management
Wilmington Regional Office Stormwater File
State of North Carolina I Environmental Quality I Energy Mineral and Land Resources
Wilmington Regional Office 1127 cardinal Drive Extension I wllnungton, NC 28405
910 796 7215
State Stormwater Management Systems
Permit No SW8 070817
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF ENERGY, MINERAL AND LAND RESOURCES
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
Pelican Point CB, LLC and HDI Holdings, LLC
Pelican Point
402 N Lake Park Blvd, Carolina Beach, New Hanover County
FOR THE
construction, operation and maintenance of one (1) infiltration trench (hereafter referred to as
infiltration system or stormwater control measure) 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 (hereafter
referred to as the Division or DEMLR) and considered a part of this permit
This permit shall be effective from the date of issuance until October 12, 2021, 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
This stormwater system has been approved for the management of stormwater runoff
as described in Section 16 of this permit The runoff from all built -upon area within the
permitted drainage area of this project must be directed into the permitted stormwater
control measure The stormwater control has been designed to handle the runoff from
25,226 square feet of impervious area
3 The maximum built -upon area allowed for the entire project is 25,226 square feet
The drainage area will be limited to the amount of built -upon area indicated in Sections
12 and 16 of this permit, and per approved plans This permit does not provide any
allocation of built -upon area for future development
The infiltration system is permitted per the Alternative Design Criteria under Section
1008 (h) The proposed system provides equal or better control, equal or better
protection of surface waters and results in no increased potential for nuisance
conditions The infiltration system can store at least 2 times the minimum design
storm, therefore a LS/VFS is not required
Page 1 of 7
State Stormwater Management Systems
Permit No SW8 070817
The following design criteria have been permitted for the infiltration trench and it must
be provided and maintained at the design condition
Drainage Area 1
a
Drainage Area acres
Onsite ft'
Offsite ft'
078
33,964
0
b
Total Impervious Surfaces ft'
Onsite, ft2
Offsite ft2
25 226
25,226
0
c
Design Storm inches
1 0
d
Trench Length feet
1,065 8
e
Trench Width feet
4 5 and 7 66
f
Trench Depth feet
1 25
Perforated Pipe Diameter in
6
h
Perforated Pipe Length, ft
10658
i
Bottom Elevation, FMSL
350
Bottom Surface Area, ft2
7 794
k
Bypass Weir Elevation, FMSL
475
1
Permitted Storage Volume ft'
4,082
m
Predevelopment 1 yr-24 hr
discharge rate, cfs
0 04
n
Type of Soil
Sand
o
Expected Infiltration Rate, in/hr
625
1/2 of the measured rate
Seasonal High Water Table FMSL
278
Time to Draw Down, hours
004
r
Receiving Stream/River Basin
Carolina Beach Yacht Basin
/ Cape Fear
s
Stream Index Number
18-87-31 2
t
Classification of Water Body
SIB
II SCHEDULE OF COMPLIANCE
1 No person or entity, Including the permittee, shall alter any component of the approved
stormwater system shown on the approved plans unless and until the Division has
approved of the revised plan
2 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
3 During construction, erosion shall be kept to a minimum and any eroded areas of the
system will be repaired Immediately If the stormwater system is 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
4 The permittee shall at all times provide the operation and maintenance necessary to
assure that all components of the permitted stormwater system function at design
condition The approved Operation and Maintenance Agreement is incorporated by
reference into this permit and must be followed in its entirety and maintenance must
occur at the scheduled intervals
Page 2 of 7
State Stormwater Management Systems
Permit No SW8 070817
5 It is the responsibility of the permit holders, Pelican Point CB, LLC and HDI Holdings,
LLC, to notify the Division of any changes in responsibility for complying with the
permit and request an ownership/name change for the stormwater permit However,
please be reminded that if the development agreement between Pelican Point CB,
LLC and HDI Holdings, LLC is dissolved, cancelled or defaults, and the Division is not
notified by Pelican Point CB, LLC to transfer the permit, then the responsibility for
permit compliance reverts back to the property owner, HDI Holdings, LLC The
Division must be notified immediately of any permit ownership changes and submit a
completed Name/Ownership form to the Division within 30 days Otherwise Pelican
Point CB, LLC and HDI Holdings, LLC will be operating a stormwater treatment facility
without a valid permit This is a violation of NC General Statue 143-215 1 and may
result in appropriate enforcement action including the assessment of civil penalties of
up to $25,000 per day 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
6 The facilities shall be constructed in accordance with the conditions of this permit, the
approved plans and specifications, and other supporting data
7 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
All stormwater collection and treatment systems must be located in either public rights -
of -way, dedicated common areas or recorded easements The final plats for the
protect will be recorded showing all such rights -of -way, common areas and
easements, in accordance with the approved plans Access to the stormwater facilities
for inspection and maintenance shall be maintained via appropriate recorded
easements at all times
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 Redesign or addition to the approved amount of built -upon area or to the
drainage area
c Further development, subdivision, acquisition, lease or sale of any, all or part of
the protect 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
d Filling in, altering, or piping of any vegetative conveyance shown on the
approved plan
e The construction of any future BUA listed on the application
10 Prior to transfer of the permit, the stormwater facilities will be inspected by Division
personnel The project and the stormwater facility must be in substantial compliance
with all permit conditions Any items not in substantial compliance must be repaired,
replaced or restored to design condition prior to the transfer Records of maintenance
activities performed to date will be required
Page 3 of 7
State Stormwater Management Systems
Permit No SW8 070817
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
III GENERAL CONDITIONS
1 Any individual or entity found to be in noncompliance with the provisions of a
stormwater management permit or the stormwater rules, is subject to enforcement
action as set forth in NCGS 143, Article 21
2 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
3 In the event that the facilities fail to perform satisfactorily 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
Additional or replacement stormwater management systems shall receive a permit
from the Division prior to construction
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, subject to the requirements of Session Law 2013-121,
e Dissolution of the partnership or corporate entity, subject to NCGS 57D-2-01(e)
and NCGS 57D-6-07,
f A name change of the current permittee,
g A name change of the project,
h A mailing address change of the permittee,
5 The permittee is responsible for compliance with all permit conditions until such time
as the Division approves the transfer request Neither the sale of the project, in whole
or in part, nor the conveyance of common area to a third party constitutes an approved
transfer of the stormwater permit
6 The permittee grants DEMLR Staff permission to enter the property during normal
business hours for the purpose of inspecting all components of the permitted
stormwater management facility
7 The permit issued shall continue in force and effect until modified, revoked, terminated
or renewed The permit may be modified, revoked and reissued or terminated for
cause The filing of a request for a permit modification, revocation and re -issuance or
termination does not stay any permit condition
8 Approved plans, calculations, supplement forms, operation and maintenance
agreements and specifications for this project are incorporated by reference and are
enforceable parts of the permit A copy of the approved plans and specifications shall
be maintained on file by the Permittee at all times
Page 4 of 7
State Stormwater Management Systems
Permit No SW8 070817
9 Unless specified elsewhere, permanent seeding requirements for the stormwater
controls must follow the guidelines established in the North Carolina Erosion and
Sediment Control Planning and Design Manual
10 The issuance of this permit does not prohibit the Director from reopening and
modifying the permit, revoking and reissuing the permit, or terminating the permit as
allowed by the laws, rules and regulations contained in Session Law 2008-211, Title
15A NCAC 2H 1000, and NCGS 143-215 1 et al
11 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 appropriate
application, documentation and the processing fee
Permit modified and reissued this the 12th day of August 2016
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
Division of Energy, Mineral and Land Resources
By Authority of the Environmental Management Commission
11--TN iI i►[Ri1:1 �9h'E:IrfLrYlrtl
Page 5 of 7
State Stormwater Management Systems
Permit No SW8 070817
Pelican Point
Stormwater Permit No SW8 070817
New Hanover 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
The checklist of items on page 2 of this form is included in the Certification
Noted deviations from approved plans and specification
Signature
Registration Number
Date
SEAL
Page 6 of 7
State Stormwater Management Systems
Permit No SW8 070817
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 weir elevation is per the approved plan
6 The bypass structure is located per the approved plans
7 A Trash Rack is provided on the 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
cc NCDEQ-DEMLR Wilmington Regional Office
New Hanover County Building Inspections
Page 7 of 7
Hall, Christine
From Hall, Christine
Sent Thursday August 11, 2016 4 15 PM
To Charles Poindexter, Engineer Jim Honeycutt (mason boro@bellsouth net)
Cc Weaver, Cameron
Subject RE Charles P Checking In
Charles / Jim,
I have had the opportunity to take a look at the additional items received on August 2"' In looking at these items, I
found two minor things that need to be addressed
1 The revised infiltration trench supplement lists the infiltration rate as "m" This appears to be a typo as this rate
was completed on the original supplement Can I get a revised version with the infiltration rate listed?
2 1 also need two sets of plans per 15A NCAC 02H 1003(g)(1) However, only one set of the revised drainage plan
was provided Can I please get a second copy?
I'm hoping these two items can be taken care of easily enough that I don't need to write another letter As always,
please let me know if you have any questions or concerns
Thank you again for your patience'
Christine
Christine Hall
Environmental Engineer
Division of Energy, Mineral and Land Resources — State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
chnstine hall@ncdenr gov
127 Cardinal Drive Ext
Wilmington, NC 28405
:= Nothing Compares�
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties
From Charles Poindexter [mailto ccpii@mac com]
Sent Thursday, August 11, 2016 8 37 AM
To Hall, Christine <Christine Hall@ncdenr gov>
Subject Re Charles P Checking In
No problem, thank you Christine Hope you are feeling better
With kind regards,
Charles C Poindexter, II
910 620 4672
ccpunmac coin
On Aug 11, 2016, at 8 18 AM Hall, Christine <Christine I lall a ncdenr sov> wrote
Charles,
I did receive the information but have not had the opportunity yet to review it I have been
battling a very nasty cold and am trying to catch up from a few days off I hope that I can look at
it today 1 hank you for your patience?
Christine
Christine Hall
Environmental Engineer
Division of Energy, Mineral and Land Resources - State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
christme hallna nedenr gov
127 Cardinal Drive Ext
Wilmington, NC 28405
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties
-----Original Message-----
FromCharles Poindexter [mailto can a,mac coin]
Sent Thursday, August 11, 2016 8 10 AM
To Hall, Christine <Christine Hall a,ncdenr gov>
Subject Charles P Checking In
Good morning Christine
Just checking in to see how everything is going with our permit I hanks for your time, I hope we
are good to go
With kind regards,
Charles C Poindexter, II
Page 1 of 1
From Jim Honeycutt <masonboro(a),bellsouth net>
Date August 1, 2016 at 8 20 22 PM EDT
To Charles Poindexter <ccmrnn mac com>
Subject Pelican Point
CNi> TyrrrVJ
>The drainage area listed in the calculations, the application, and
the supplement has been corrected
he calculations for the storage volume required is shown on
page 2 (about midpage) of the calculations
The trench width will be 7'8" in most places The trenches in the
pool area will be 4'6" This has been clarified on drawing C3
he width of the trench that was projecting into the 30' setback
was changed to 4'6" in order to keep it out of the setback All trenches are now outside the 30'
setback
Soil boring 3 is now shown on the drawing along with existing
and proposed elevations and the SHWT elevation The elevation of the SHWT has been changed on
the supplement to 3 5
he elevation of the bottom of the trench will be 3 5 The
elevation of the SHWT at its highest point is 2 78 The detail on sheet C3 has been corrected
-->The monitoring well in question has been moved
3 The option for eliminating the vegetated buffer by doubling the required storage volume and using one
half the infiltration rate was used The narrative has been updated to reflect this
4 An existing note to tie gutters to the pipes in trench 1 & 2 was moved and enlarged so as to be more
visible
5 Infiltration trench 0&M agreement attached
6 N/A
7 N/A
Call if you have any questions /
Jim Honeycutt
910-512 0729
RECEIVE'D� S
8/2/2016 AUG 0 2 2016 Life` S
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NARRATIVE ON PELICAN POINT
402 N LAKE PARK BLVD
CAROLINA BEACH, NORTH CAROLINA AU
STORMWATER MANAGEMENT PLAN ey??415
A stormwater permit (SW8 070817) was issued for this site in 2007
However, the site was never developed Since that time the owner of the
property has changed The new owner has developed a different plan for
the site The purpose of this application is to modify that original permit to
accommodate development of the site per the new plan It is planned to
collect and treat stormwater in an infiltration system under the same rules
in effect in 2007
The site located at 402 Lake Park Blvd is approximately 985 acres
(42,893 square feet) with 3942 square feet below the mean high water line
8429 square feet of the site are in the AEC The project will consist of a
four story building with 36 units on piles with associated parking The
project has a small swimming pool adjacent to the AEC
The site has one drainage basin with an area of 0 78 acres Approximately
0 11 acres of pervious area will drain offsite after development Runoff
from the roof will be routed directly into infiltration trenches on each side of
the building Runoff from the remainder of the site will be routed via
surface grading to catch basins and then into a series of smart boxes The
smart boxes have an internal weir that directs the water into the infiltration
system trenches All trenches are interconnected Overflow from one
smart box drains to the next smart box and so on
The elevation of the seasonal high water table (SHWT) varies from
elevation 1 99 at boring B-2, 2 41 at B-3, and 3 69 at boring B-1 Infiltration
rates vary on the site from 12 5 to 18 5 inches per hour
Since no vegetative filter is provided, the infiltration system was designed
with a storage volume twice the required storage volume for the first 1" of
runoff in the drainage basin The infiltration rate used in the design was
one half of the lowest infiltration rate from the soil reports The system has
also been designed to pass the 10 year and 50 year storms with a non -
erosive velocity
The site contains coastal wetlands of which about 100 square feet will be
affected by the pipe discharging from the site A major CAMA permit for
the site has been approved with conditions
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
1
Protect 15023
7/5/16 - Revised 7/30/16
Atotal =
38879
Atotal = 0 893
acres
total site area above mean high water line before development
43560
33964
Abmp
43560
Abmp = 0 78
acres
total area draining to infiltration system
Agave =
14458Agave
= 0 332
Paved areas
43560
910
Amisc =
43560
ta•misc = 0 021
acres
Abldg =
9858
Abldg = 0 226
acres
bldg area
43560
Aimp =
Apave + Amrec + Abldg A,,,,p
= 0 579
acres total impervious area
4822
Aoffsite =
Aoffsde = 0 111
acres
pervious area draining offsite
43560
Aother =
/
Abmp — Aimp — (Aoffsde)
Aother
= 0 09 pervious area draining to infiltration system
Cp,e = 30 pre -development C C,mp = 95 paved area C Cbldg = 0 90 building C
Aother (Apave + Amisc Abldg
Ccomp = Cpfe + Ctmp + Cbldg )I
Abmp Abmp Abmp
Camp = 0 726 composite C (post -development)
la
L = 320 ft hydraulic length H = 8 ft height �Qy�B��
385 pt;G 9 2 NIB
L3
H
TO = 128 Tc = 2 75 minutes time of concentration BY ��—
T = if(Tc < 5, 5,Tc� T = 5 minutes Time of duration (use 5 minutes min.)
Intensity -Duration -frequency Relationships
Values of G and H`
R G H
2 182 26
10 268 32
25 326 35
50 364 36
100 403 37
R= Return Period
Source New Hanover County Stormwater manual
G2
stet to
Q°rlE°
/C
2d•'Q�
�'�s �R'CiNB�P.•�,t.w
'eretttu ltl
%t t4
G2 = 182 Hz = 26 12 = 12 = 5 87 in/hr 2 year storm intensity
(H2 + T)
Gto = 268 Hto = 32 Ito = /H + T
G1 Ito = 7 24 in/hr 10 year storm intensity
to /
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
2
G25 = 326 H25 = 35 G25
/
125 = \H25 + T)
G50
G50 = 403 H50 = 37 150 = /H50 + T1
Compute runoff rates
Q10pre = Cpre 110 (Abmp)
Q10pre = 1 69 cfs
Q10 — Ccomp 110 Abmp/
Q10 = 4 1 cfs
Q50 = Ccomp 150 (Abmp)
Q50 = 5 43 cfs
125 = 8 15 in/hr 25 year stone intensity
150 = 9 595 m/hr 50 year storm
total pre -development runoff from 10 yr storm
post -development discharge rate from 10 yr storm
post -development discharge rate from 50 yr storm
Volume of runoff from developed area of site
IA = Aimp IA = 0 743
Abmp
Rv=005+091A Rv=0718
RD = 1 0 in runoff depth
Volumerequved = 3630 Rp Rv Abmp Volumereginred = 2033
P1 = 2 79
P2 = 3 38 in
P10 = 5 18 in
P25 = 6 45 in
P50 = 7 57
P100 = 8 84 in
Soil type = Fine to medium sand
Apave Abldg Aother
CN = — 98 + 98 + 39
Abmp Abmp Abmp
1000
S = CN -10 S=3394
(P1 - 0 2 S)2
Rldepth = + 8 S Rldeptn = 0 81 n
P
1
R1voj = Rldepth (Abmp) 43560 112 R1vo1=2291
Rldepth (Abmp) 1 t
T1p = 1 39 (Q10) (12) 43560 60
VG'VE
AUG 0 11111
BY
CN = 75
runoff depth
cubic feet
Curve No
runoff volume to infiltration system
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
3
T1p = 6 7 minutes time to peak flow
T1p
OT1 = OT1 = 0 67 time increment for routing 1 year storm
10
Now compute runoff depth and time to peak for 10 yr storm
�Pto-02 S)2
R10depth = + 8 S R1 Odepth = 2 566 in runoff depth
Pto
R10vdj = R10depth (Abmp) 43560 112 R1Ovpi = 7263 cubic feet
R10depth (Abmp) 1 1
T10p = 1 39 (Qto ) (12) 43560 60
T10p = 21 25 minutes time to peak flow
T10p
OT10 = — AT10 = 2 125 time increment for routing 10 year storm
10
Now compute runoff depth and time to peak for 50 yr storm
�Pso-02 S12
R50depth = R50depth = 4 617 in runoff depth
Pso + 8 S1
R50voi = R50depth (Abmp) 43560 112 R50vol = 13068 cubic feet
T50 _ R50depth (Abmp) 1 43560 1
p 1 39 (Qso) (12) 60
T50p = 28 86 minutes time to peak flow
T50p
AT50 = — AT50 = 2 886 time increment for routing 50 year storm
10
Develop stage -storage function
m= 0 6 n= 1 6 contouro = 3 5 increment = 5 ft
12
trenchlength2 = 946 69 length of trench 7 66 ft wide width2 = 7 + 8 ft
12
runoff volume to infiltration system
runoff volume to infiltration system
trenchlengthl = 119 1 length of trench 4 5 ft wide widthl = 4 5 ft
trenchlength = trenchlengthl + trenchlength2 trenchlength = 1065 79
bottom areal = trenchlengthl widthl bottom areal = 535 95 sq ft
bottom_area2 = trenchlength2 width2 bottom_area2 = 7 258 x 103 sq ft
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
4
contourn = contourn_1 + increment
am = bottom_area1 + bottom_area2
contourm = contours of proposed trench
am = area of contours of proposed trench
35
7794
3 708
7794
3 917
7794
4 125
7794
4 333
7794
4 542
7794
4 75
7794
yr = 0 419 assumed void ratio of stone ( 4) + pipe volume
an-1 + an
vn = 2 (contourn - contourn_1) yr incremental volume (cubic ft )
vm =
SO = 0 initial storage
Sri = Sn_1 + vn cumulative storage (cubic ft )
Sm =
0
680
1361
2041
2721
3402
4082
0
6803
6803
680 3
6803
680 3
680 3
Volumerequired = 2 033 x 103
Volume provided S6 = 4082
InZn = In(stagen)
InZn =
-1 5686
-0 8755
-0 47
-0 1823
00408
02231
x = submatrix(InZ, 2, 5, 0, 0)
must be equal to or greater than
InSn = In(Sn)
InSn =
65226
72157
76212
79089
8 132
83144
stagen = contourn - contour0
stagen =
0208
0 417
0 625
0 833
1 042
1 25
2 Volumerequired = 4067 OK
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
y = submatrix(InS, 2, 5, 0, 0)
slope=slope(x,y) slope =1
b = intercept(x , y) b = 8 09
1
- /
KS = eb KS = 3 266 x 103 S II` m slope
Zestm
KS
Should compare closely with
Zestm =
stagem =
0
0
0208
0208
0 417
0 417
0 625
0 625
0 833
0 833
1 042
1 042
1 25
1 25
Size emergency spillway to pass 50 year peak flow
Cw = 3 0 weir coefficient
Hew = 37 driving head over emergency weir (ft )
Qs0
Lw = 5
Cw Hew
Lw = 2 98 ft (minimum) Lw = 3 ft length chosen
Ecr = 4 75 crest elev of overflow weir
u = 0 25 v = 1 25
Continue with routing calcs
Since infiltration rates from 12 5 to 18 5 inches per hour can be expected, use an average of 112 lower rate
125
— in
K = 2 K = 1 447 x 10 4 cfs unit infiltration rate
hr ft2
Route 10 year storm
OT10
AT = 1 5 Q = Q10 Q = 4 098 TP = T10P
set variables for storm to be routed iter = 70 number of iterations u = 0 der m = 0 5
Check mass balance of matrix calcs
Storage = Miter.2 Storage = 823
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
0
iter
Inflowtotal = Y, T(Mv,1) (Mv,0 - My-1,0) 601 Inflowtotal = 7250 cubic feet
v = 1
iter
Outflowtotal = Y T(Mv,4 + Mv,5) (Mv 0 - My-1,0) 601 Outflowtotal = 6426 cubic feet
v = 1
Inflowtotal - Outflowtotal = 823 MUST BE REASONABLY CLOSE TO Storage = 823 O K
iter
Infiltration = I T(Mv,4) (Mv,0-My-1,0) 60� Infiltration = 6426 cubic feet
v = 1
der
Outflowv,,er = E T(Mv,5) (Mv,0 - My-1,0) 601 OutflowW1ef = 0 cubic feet
v = 1
Display a portion of routing results
timeu = Mu 0 inflowu = Mu 1 storageu = Mu 2 stageu = Mu 3 + contour0 infiltrationu = Mu 4 weiru = Mu 5
maxelevation = max(stage) maxelevation = 4 56 maxdischarge = max(weir) maxdischarge = 0
(See next page for routing results)
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
minutes cfs cubic feet ft cfs cfs
timeu =
inflowu =
storageu =
stageu =
infiltrationu = weiru =
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
CHAINSAW ROUTING FOR 10 YR STORM
5
4
3
2
1
- - - - -
- - - -
- - - - -
- - - - - - -
0
0
20
40
60
80 11
TIME (minutes)
INFLOW
— — INFILTRATION
— — WEIR
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
0
Route 50 year storm
OT50
AT = z Q = Q50 Q = 5 429
set variables for storm to be routed
TP = T50P
der = 70 number of iterations
Check mass balance of matrix calcs
Storage = Miter,2 Storage = 3272
der
Inflowtotal = I LL(Mv 1) (Mv 0 - My-1 0) 601
v=1
der
Outflowtotal = Y T(Mv, 4+Mv,5) (Mv,0-My-1,0) 60T
v = 1
Inflowtotal = 12793
u= 0 iter m= 0 5
cubic feet
Outflowtotal = 9520 cubic feet
Inflowtotal - Outflowtotal = 3272 MUST BE REASONABLY CLOSE TO Storage = 3272 O K
der
Infiltration = I T(Mv,4) (Mv,0 - Mv_1,0) 60T Infiltration = 6499 cubic feet
v=1
iter
Outflow,,er = Y' T(Mv, 5) (Mv, 0 - My-1 0) 601 OutflowW1ef = 3022 cubic feet
v = 1
Display a portion of routing results
time, = Mu,0 mflowu = Mu 1 storage, = Mu,2 stageu = Mu 3 + contour0 mfdtrationu = Mu 4 weiru = Mu 5
maxelevatlon = max(stage) maxelevatlon = 5 12
maxdlscharge = max(weir)
maxdlscharge = 1 988
(See next page for routing results)
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
10
minutes
timeu =
cfs
inflowu =
0
003
0 13
03
052
08
1 12
148
188
229
271
314
355
395
431
463
491
5 13
53
54
543
54
53
5 13
491
463
435
407
382
358
335
3 14
294
276
2 58
2 42
2 27
cubic feet
storageu =
ft
stageu =
35
35
35
35
35
35
35
351
353
356
36
366
372
379
388
397
407
418
429
44
452
463
474
484
492
499
504
507
509
5 11
5 11
5 12
5 11
51
5 09
5 08
507
cfs cfs
infiltration, =
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
11
LL
U
CHAINSAW ROUTING FOR 50 YR STORM
I /
I \
I \
I \
I \
I \
I \
— INFLOW
— — INFILTRATION
— — WEIR
50 inn
TIME (minutes)
Drainage Calculations for Pelican
Point 402 N Lake Park Blvd Carolina
12
Check drawdown time
S6 ft3
drawdown =
K a1 ft2
drawdown = 1 006 hr
Size pipe and outlet structure
n = 012
(Q50 n)0375
D = 16
s
5
rD12 in
A J
2
s = 006
D = 14 994 in
A = 1 227
P=TrD P=3927
A
R =? R=0313
use 12 in min D = 1 25 ft diameter of pipe
so ft Cross sectional area of flow when flowing full
ft when flowing full
Hydraulic radius when flowing full
Voutlet = l 11 491J �R�0 67 50 5 Voutlet = 4 412 fps
n
From Figure 8 06 b 1 and Figure 8 06 b 2 choose Zone 1
La = 3 D La = 3 75 ft - minimum length of apron from figure 8 06b2
W = 4 D W = 5 ft - minimum width of apron from figure 8 06b2
diam = 3 diameter of stone in inches
dmax = 1 5 diam dmax = 4 5 max stone diameter
t = 12 in min thickness of apron in inches
Hall, Christine
From Hall, Christine
Sent Friday, July 29, 2016 104 PM
To Jim Honeycutt
Cc Charles Poindexter
Subject RE Pelican Point Stormwater Project No SW8 070817
Jim,
An extension until August 3rd is fine with me Thank you for the email)
Christine
Christine Hall
Environmental Engineer
Division of Energy, Mineral and Land Resources — State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
chnstine hall@ncdenr gov
127 Cardinal Drive Ext
Wilmington, NC 28405
�Nothmg Compares
Email correspondence to and from this address Is subject to the
North Carolina Public Records Law and may be disclosed to third parties
From Jim Honeycutt [mailto masonboro@bellsouth net]
Sent Friday, July 29, 2016 12 29 PM
To Hall, Christine <Christine Hall@ncdenr gov>
Cc Charles Poindexter <ccp❑@mac com>
Subject Pelican Point - Stormwater Project No SW8 070817
The purpose of this email is to request an extension to the required submittal date for additional info from August 1,
2016 to August 3, 2016
Please let me know that you have received this
Thanks,
Jim Honeycutt
910-512-0729
k.
Hall, Christine
From Hall, Christine
Sent Tuesday, July 26, 2016 107 PM
To Jim Honeycutt
Cc Charles Poindexter
Subject RE Pelican Point - Stormwater Project No SW8 070817
Jim,
Thanks for the e-mail This calculation is missing from the set that was submitted In looking at the calculation on your
attachment, it looks like you only considered the impervious area draining to the system You also need to consider the
pervious area as well Granted, it won't contribute the complete 1" of rainfall runoff, but it still will contribute a fraction
of it The required volume will need the consider the entire drainage area, both pervious and impervious areas
Also, in looking at this new calculation, the required volume is low based on the site design I looked back at your
calculations and it looks like the areas listed on page 1 are not quite adding up For instance, the total impervious area
lust includes the pavement and the miscellaneous areas Why is the building area not included? Also the sum of the
paved areas, miscellaneous areas, building area, and other pervious areas do not appear to add up to the total drainage
area
Please let me know if you have any other questions
Christine
Christine Hall
Environmental Engineer
Division of Energy Mineral and Land Resources - State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
christine hall@ncdenr gov
127 Cardinal Drive Ext
Wilmington NC 28405
-:5-"Nothing Compares
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties
From Jim Honeycutt [mailto masonboro@bellsouth net]
Sent Monday, July 25, 2016 3 18 PM
To Hall, Christine <Chnstine Hall@ncdenr gov>
Cc Charles Poindexter <ccpii@mac com>
Subject Pelican Point - Stormwater Project No SW8 070817
This email is in reference to item 1 b on your request for more information I've attached a copy of page 3 of the
calculations with what I think is the calculation you are requesting circled Could you verify that this is the calculation
you are requesting and, if not, help me understand what it is you need?
Energy Mineral &
Land Resources
ENVIRONMENTAL QUALITY
July 22, 2016
Charles C Poindexter, II, Manger
Pelican Point CB, LLC, Developer
7923 Reunion Rd
Wilmington, NC 28411
Subject Request for Additional Information
Stormwater Project No SW8 070817
Pelican Point
New Hanover County
Dear Mr Poindexter and Mr Huth
PAT McCRORY
Governor
DONALD R VAN DER VAART
Secretary
TRACY DAVIS
Director
Robert Huth, Manager
HDI Holdings, LLC, Property Owner
5929 Market St
Wilmington, NC 28405-3615
The Wilmington Regional Office received and accepted a modified Express State Stormwater
Management Permit Application for Pelican Point on July 15, 2016 A preliminary in-depth review of
that information has determined that the application is not complete The following information is needed
to continue the stormwater review
15A NCAC 02H 1003(g)(7) Provide technical information showing final numbers, calculations,
assumptions, drawings and procedures associated with the stormwater management measures
including
The drainage area listed in the calculations (38,893 ft') is different than the area listed in
the application and supplement (38788 ft') Please confirm the drainage area of the
infiltration trench is presented consistently among the application documents
✓b' As discussed in the submittal meeting, please provide the calculations demonstrating the
minimum required volume or provide a citation of where this calculation can be found
the revised calculations submitted on July 1 Ith and accepted on July 15th do not appear
Xto contain this information
The infiltration trench supplement and plans indicate that the width of the infiltration
trench will be 5 ft However, the detail on C3 indicates the width will be 4 feet Please
confirm the width of the infiltration trench
15A NCAC 02H 1008(d)
/a— Under the 1995 Rules, infiltration systems must be a minimum of 30 feet from non -SA
surface waters According to sheet C3, a very small portion of the infiltration trench
appears to be within the 30 feet setback from the mean high water line Please confirm b h S~
that the infiltration trench is located outside of the 30-foot setback , :;O9i"!'�
Please provide the existing ground elevation in the vicinity of solCboring�3't3 support t,41 " �6
the identified seasonal high water table (SHWT) elevations Additionally, —please identify 1 ��
,tlie highest elevation of the SHWT on the supplement to document the limiting elevation
for the design of the infiltration system (refer to Item 2 c of this letter)
tic According to the supplement and the detail on sheet C3, the bottom elevation of the
trench is proposed to be 3 25 It However, the profile from boring B-I to smart box 4
appears to indicate that the bottom of the trench will be at an elevation of 3 5 ft, which
appears to approximately be at the 6-inch minimum required separation from the SHWT
near Smart Box I Please confirm the elevation of the trench bottom and ensure that it
provides at least a 6-mch separation from the SHWT
u/d The plans indicate a monitoring well will be located west of the proposed infiltration
trench Please re -locate this monitoring well to within the vicinity of french 3 or the
western parts of french 1 or 2
State of North Carolina I Environmental Quality I Energy Mineral and Land Resources
Wilmington Regional Office 1 127 Cardinal Drive Extension I Wilmington NC 28405
910 796 7215
State Stormwater Permit No SW8 070817
Page 2 of 2
/I5A NCAC 02H 1008(c)(4) and 1008(h) I he overflow from an infiltration system must be
directed to a vegetated filter strip During the submittal meeting, options to eliminate this
requirement for a vegetated filter strip In accordance with Section 16 3 9 of the NC BMP Manual
were discussed Without the calculation demonstrating how the minimum required storage
volume of 2,562 ft' was determined (refer to item 1 b of this letter), it is not clear which
alternative design option is being utill7ed to waive the requirement for a vegetated filter strip If
one of the alternative designs presented in Section 16 3 9 of the NC BMP manual is being
utilized, please provide the calculations demonstrating how the infiltration system meets the
alternative design and update the narrative to discuss which alternative design was selected
✓4 15A NCAC 021-1 1005(a)(3)(13)(m) Please either demonstrate how the roof runoff will be
directed to the stormwater collection and/or treatment system or include a note on the plans to
direct the roof runoff to the stormwatcr collection system
V15A NCAC 0214 1003(g)(8) I he proposed stormwater treatment system is an infiltration trench,
however, the provided operation and maintenance (O&M) agreement is for an infiltration basin
Please provide the operation and maintenance agreement appropriate for the proposed stormwater
treatment system
6 Due to the relatively minor nature of these comments, the express additional information review
fee has been waived
7 Please keep in mind that changing one number may change other numbers and require the
calculations, supplements, and other supporting dowmentation to be updated Verify all numbers
are correct to ensure consistency in the application documents
Please note that this request for additional information is in response to a preliminary review The
requested information should be received in this Office prior to August 1, 2016, or the application will be
returned as incomplete If the project is returned and you wish to re -submit to the Express Program, you
will need to reschedule the project through the Express Coordinator for the next available review date and
will need to resubmit all of the required items at that time, including the application fee
If you need additional time to submit the information, please email or fax your request for a time
extension to the Division at the email address or fax number at the bottom of this letter 7 he request must
Indicate the date by which you expect to submit the required information, which shall be no later than 5
business days past the original due date
The construction of any impervious surfaces other than a construction entrance under an approved
Sedimentation Erosion Control Plan, is a violation ofNCGS 143-215 1 and is subject to enforcement
action pursuant to NCGS 143-215 6A
Please label all packages and cover letters as "Express' and reference the project name and State assigned
project number on all correspondence If you have any questions concerning this matter, please feel free
to call me at (910) 796-7215 or email me at christine hall@ncdenr gov
Sincerely,// /
C1J- 4 /l G.&/n
Christine Hall
Environmental Engineer
GDS/canh \\\Stormwater\Permits & Projects\2007\070817 HD\2016 07 addmfo 070817
cc James Honeycutt, Jr, PE
Wilmington Regional Office Stormwater File
State of North Carolina I En"ronmental Quality I Energy Mineral and Land Resources
Wilmington Regional Office 1127 Cardinal Drive Extension I Wilmni NC 28405
910 796 7215
Hall, Christine
From
Hall, Christine
Sent
Friday, July 22, 2016 12 45 PM
To
Charles Poindexter, Engineer Jim Honeycutt (masonboro@bellsouth net)
Cc
Weaver, Cameron
Subject
request for additional info - Pelican Point, SW8 070817
Attachments
2016 07 addinfo 070817 pdf
Gentlemen,
Attached is a pdf of the request for additional information for the modification to Pelican Point, SW8 070817 Please let
me know if you have any questions or concerns
Thanks,
Christine
Christine Hall
Environmental Engineer
Division of Energy, Mineral and Land Resources - State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
chnshne hall@ncdenr gov
127 Cardinal Drive Ext
Wilmington, NC 28405
-�'--^Nothmg Compares.,.
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties
Hall, Christine
From Hall Christine
Sent Wednesday, July 20, 2016 2 23 PM
To Charles Poindexter
Subject RE Charles P - CORRECTED App page 3
Thanks The transfer has been approved and the modification is next up in line of projects I need to review I have one
on my desk I need to finish up first but hopefully I can get started looking at it tomorrow
Christine Hall
Environmental Engineer
Division of Energy Mineral and Land Resources — State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
christine hall@ncdenr gov
127 Cardinal Drive Ext
Wilmington, NC 28405
10- -^/'Nothing ComparesN_
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties
From Charles Poindexter [mailto ccp❑@mac com]
Sent Wednesday, July 20, 2016 122 PM
To Hall, Christine <Christine Hall@ncdenr gov>
Subject Charles P - CORRECTED App page 3
Hey Christine
Here is the corrected applicant section for Pelican Point CB, LLC IIow are we looking on time do you think?
No rush, just curious
1