SW8071026_HISTORICAL FILE_20080410

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW8 011021v
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
2oog 0`110
YYYYMMDD

\O�dF WAT f9
r
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Coleen H. Sullins Director
Division of Water Quality
April 10, 2008
Bruce Shell, New Hanover County Manager
New Hanover County Fire Department
230 Government Center Drive, Suite 195
Wilmington, NC 28403
Subject: State Stormwater Permit No. SW8 071026
New Hanover County Murrayville Fire Station
High Density Commercial Project
New Hanover County
Dear Mr. Shell:
The Wilmington Regional Office received a complete Stormwater Management Permit
Application for New Hanover County Murrayville Fire Station on April 8, 2008. Staff review of
the plans and specifications has determined that the project, as proposed, will comply with the
Stormwater Regulations set forth in Title 15A NCAC 2H.1000. We are forwarding Permit No.
SW8 071026 dated April 10, 2008, for the construction of the subject project.
This permit shall be effective from the date of issuance until April 10, 2018, 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 sixty (60) 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, P.O. Drawer 27447, Raleigh, NC 27611-7447. Unless such demands
are made this permit shall be final and binding.
If you have any questions, or need additional information concerning this matter, please
contact Rhonda Hall, or me at [phone].
Sincerely,
�i.u,oCa.Y1�i:QDao l�
Edward Beck
Regional Supervisor
Surface Water Protection Section
ENB/ rbh: S:\WQS\STORMWATER\PERMIT\071026.apr08
cc: Jody Bland, E.I., Norris, Kuske & Tunstall Consulting Engineers, Inc.
New Hanover County Building Inspections
City of Wilmington Development Services
Rhonda Hall
CWilmington-Regional-Office?
CenntTal-Files
NOCarolina
AWtlrn!!y
North Carolina Division of Water Quality 127 Cardinal Drive Extension Wilmington, NC 28405 Phone [phone]
Wilmington Regional Office Internet: www.ncwatcrauality org Fax [phone]
An Equal Opportunity/Affirmative Action Employer— 50% Recycled/10%Post Consumer Paper
Customer Service
1-877-623-6748

State Stormwater Management Systems
Permit No. SW8 071026
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
STATE STORMWATER MANAGEMENT PERMIT
HIGH DENSITY COMMERCIAL DEVELOPMENT
In accordance with the provisions of Article 21 of Chapter 143, General Statutes of
North Carolina as amended, and other applicable Laws, Rules, and Regulations
PERMISSION IS HEREBY GRANTED TO
Bruce Shell and New Hanover County Fire Department
New Hanover County Murrayville Fire Station
Murrayville Road, Wilmington, New Hanover County
FOR THE
construction, operation and maintenance of a wet detention pond(s) in compliance with
the provisions of 15A NCAC 2H .1000 (hereafter referred to as the "stormwater rules')
and the approved stormwater management plans and specifications and other
supporting data as attached and on file with and approved by the Division of Water
Quality and considered a part of this permit.
This permit shall be effective from the date of issuance until April 10, 2018, and shall be
subject to the following specified conditions and limitations:
I. DESIGN STANDARDS
This permit is effective only with respect to the nature and volume of stormwater
described in the application and other supporting data.
2. This stormwater system has been approved for the management of stormwater
runoff as described in Section 1.6 on page 3 of this permit. The stormwater
control has been designed to handle the runoff from 51,141 square feet of
impervious area.
3. The tract will be limited to the amount of built -upon area indicated on page 3 of
this permit, and per approved plans.
4. All stormwater collection and treatment systems must be located in either
dedicated common areas or recorded easements. The final plats for the project
will be recorded showing all such required easements, in accordance with the
approved plans.
5. The runoff from all built -upon area within the permitted drainage area(s) of this
project must be directed into the permitted stormwater control system.
Page 2 of 7

State Stormwater Management Systems
Permit No. SW8 071026
(-1
The following design criteria have been provided in the wet detention pond and
must be maintained at design condition:
a. Drainage Area, 9cres:
Onsite, ft
Offsite, ftz:
b. Total Impervious Surfaces, ft2:
C. Design Storm, inches:
d. Average Pond Design Depth, feet:
e. TSS removal efficiency:
f. Permanent Pool Elevation, FMS�:
g. Permanent Pool Surface Areq, ft
h. Permitted Storage Volume, ft :
i. Temporary Storage Elevation, FMSL:
j. Controlling Orifice:
k. Permitted Forebay Volume, ft3:
I. Receiving Stream/River Basin:
M. Stream Index Number:
n. Classification of Water Body:
II. SCHEDULE OF COMPLIANCE
3.50
151,579
None
51,141
1
3.06
90%
35.0
8,121
5,129
35.6
1.25" 0 pipe
3,740
Smith Creek / Cape Fear
18-74-63
"C; Sw"
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.
During construction, erosion shall be kept to a minimum and any eroded areas of
the system will be repaired immediately.
The permittee shall at all time provide the operation and maintenance necessary
to assure the permitted stormwater system functions at optimum efficiency. The
approved Operation and Maintenance Plan must be followed in its entirety and
maintenance must occur at the scheduled intervals including, but not limited to:
a. Semiannual scheduled inspections (every 6 months).
b. Sediment removal.
C. Mowin.9 and re -vegetation 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 outlet structure, orifice device, flow
spreader, catch basins and piping.
Cl. Access to the outlet structure must be available at all times.
4. Records of maintenance activities must be kept and made available upon
request to authorized personnel of DWQ. The records will indicate the date,
activity, name of person performing the work and what actions were taken.
5. Decorative spray fountains will not be allowed in the stormwater treatment
system.
6. The facilities shall be constructed as shown on the approved plans. This permit
shall become void unless the facilities are 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
Page 3 of 7

State Stormwater Management Systems
Permit No. SW8 071026
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.
8. 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.
9. Access to the stormwater facilities for inspection and maintenance shall be
maintained via appropriate recorded easements at all times.
10. 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.
11. Prior to the construction of any permitted future areas shown on the approved
plans, the permittee shall submit final site layout and grading plans to the
Division for approval.
12. A copy of the approved plans and specifications shall be maintained on file by
the Permittee at all times.
13. 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 completed Name/Ownership Change Form signed by both parties, to
the Division of Water Quality, accompanied by the supporting documentation as
listed on page 2 of the form. The approval of this request will be considered on
its merits and may or may not be approved.
2. The permittee is responsible for compliance with all permit conditions until such
time as the Division approves the transfer request.
Page 4 of 7

State Stormwater Management Systems
Permit No. SW8 071026
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.
4. 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.
5. 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.
6. The permittee grants DENR Staff permission to enter the property during normal
business hours for the purpose of inspecting all components of the permitted
stormwater management facility.
7. The permit remains 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. 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.
9. Approved plans and specifications for this project are incorporated by reference
and are enforceable parts of the permit.
10. The permittee shall notify the Division of any name, ownership or mailing
address changes at least 30 days prior to making such changes.
11. The permittee shall submit a permit renewal request at least 180 days prior to
the expiration date of this permit. The renewal request must include the
appropriate documentation and the processing fee.
Permit issued this the 10t' day of April, 2008.
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
for Caleen H. Sullins, Director
Division of Water Quality
By Authority of the Environmental Management Commission
Page 5 of 7

NEW HANOVER COUNTY CONTRACP # 08-0156
NKT #07044
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
T his form may he photocopied for use as an original
1. GENERAL INFORMATION
1. Applicants name (specify the name of the corporation, individual, etc. who owns the project):
New Hanover County Fire Department
2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance):
Bruce Shell New Hanover County Manager
3. Mailing Address for person listed in item 2 above: .
230 Government Center Drive, Suite 195
City: Wilmington State: NC Zip: 28403
Telephone Number: [phone]
4. Project Name (subdivision, facility, or establishment name — should be consistent with project name on
plans, specifications, letters, operation and maintenance agreements, etc.):
New Hanover County Murrayville Fire Station
5. Location of Project (street address):
Road
City:
6. Directions to project (from nearest major intersection):
County: New Hanover
located approximately 2,000 feet East of intersection of SR 1322 and US 117
7. Latitude: 340 17' 31 "N Longitude
770 52' 3"W
8. Contact person who can answer questions about the project:
Name: J. Phillip Norris, P.E. / Jody Bland, E.I. Telephone Number:
II. PERMIT INFORMATION
1. Specify whether project is (check one)
X New
Renewal
of project
[phone]
S�o�
Modification
Form SWU-101 Version 3.99
Page 1 of 4

NEW HANOVER COUNTY CONTRACT # 08-0156
2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the
Existing permit number N/A And its issue date (if known) N/A
3. Specify the type of project (check one):
Low Density x High Density Redevelop
4. Additional Project Requirements (check applicable blanks):
CAMA Major X Sedimentation/Erosion Control
General Permit Other
404/401 Permit NPDES Stormwater
Information on required state permits can be obtained by contacting the Customer Service Center at
1-877-623-6748.
III. PROJECT INFORMATION
In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative
(one to two pages) describing stormwater management for the project.
Stormwater
2. Stormwater runoff from this project drains to the Cape Fear River Basin.
3. Total Project Area: 3.5 AC 4. Project Built Upon Area: 37+/- %
5. How many drainage areas does the project have? 1
6. Complete the following information for each drainage area. If there are more than two drainage areas in the
project, attach an additional sheet with the information for each area provided in the same format as below.
Basin Information
Drainage Area 1
Drainage Area 2
Receiving Stream Name
Smith Creek
Receiving Stream Class
$-1 y — (03 C- S� p
Drainage Area
151,579 SF / 3.50 AC
Existing Impervious * Area
0
Proposed Impervious* Area
51,141 SF / 1.17 AC
% Impervious* Area (total)
37%
Impervious* Surface Area
Drainage Area I
Drainage Area 2
On -site Buildings
13,530 SF / 0.31 AC
On -site Streets (combined)
35,878 SF / 0.82 AC
On -site Parkin (combined)
On -site Sidewalks
1,733 SF / 0.04 AC
Other on -site (future)
Off -site
N/A
Total: 51,141 SF / 1.17 AC
Total:
* Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas
sidewalks, gravel areas, etc.
Form SWU-101 Version 3.99 Page 2 of 4

NEW HANOVER COUNTY CONPRACP # 08-0156
7. How was the off -site impervious area listed above derived? N/A
IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
The following italicized deed restrictions and protective covenants are required to be recorded for all
subdivisions, outparcels and future development prior to the sale of any lot. If lot sizes vary significantly, a
table listing each lot number, size and the allowable built -upon area for each lot must be provided as an
attachment.
1. The following covenants are intended to ensure ongoing compliance with state stormwater management permit
number us issued by the Division of Water Quality. These covenants may
not be changed or deleted without the consent of the State.
2. No more than square feet of any lot shall be covered by structures or impervious materials.
Impervious materials include asphalt, gravel, concrete, brick, stone, slate or similar material but do not include
wood decking or the water surface of swimming pools.
3. Swales shall not be filled in, piped, or altered except as necessary to provide driveway crossings.
4. Built -upon area in excess of the permitted amount requires a state stormwater management permit modification
prior to construction.
5. All permitted runo/ffrom outparcels or future development shall be directed into the permitted stormwater control
system. These connections to the stormwater control system shall be performed in a manner that maintains the
integrity and performance of the system as permitted.
By your signature below, you certify that the recorded deed restrictions and protective covenants for this project
shall include all the applicable items required above, that the covenants will be binding on all parties and persons
claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted
without concurrence from the State, and that they will be recorded prior to the sale of any lot.
V. SUPPLEMENT FORMS
The applicable state stormwater management permit supplement form(s) listed below must be submitted for
each BMP specified for this project. Contact the Stormwater and General Permits Unit at [phone] for
the status and availability of these forms.
Form SWU-102
Form SWU-t03
Form SWU-104
Form SWU-105
Form SWU-106
Form SWU-107
Form SWU-108
Form SWU-109
Wet Detention Basin Supplement
Infiltration Basin Supplement
Low Density Supplement
Curb Outlet System Supplement
Off -Site System Supplement
Underground Infiltration Trench Supplement
Neuse River Basin Supplement
Innovative Best Management Practice Supplement
Form SWU-101 Version 3.99 Page 3 of 4

NEW HANOVER COUNTY cONTRACP N 08-0156
V1. SUBMITTAL REQUIREMENTS
Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ).
A complete package includes all of the items listed below. The complete application package should be
submitted to the appropriate DWQ Regional Office.
1. Please indicate that you have provided the following required information by initialing in the space provided
next to each item.
Original and one copy of the Stormwater Management Permit Application Form
One copy of the applicable supplement form(s) for each BMP
Permit application processing fee of $420 (payable to NCDENR)
Detailed narrative description of stormwater treatment / management
Two copies of plans and specifications, including:
- Development / Project name
Engineer and firm
Legend
North arrow
Scale
- Revision number & date
Mean high water line
- Dimensioned property / project boundary
Location map with named streets or NCSR numbers
Original contours, proposed contours, spot elevations, finished Floor elevations
Wetlands delineated, or a note on plans that none exist
Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations
Drainage areas delineated
Vegetated buffers (where required)
VII. AGENT AUTHORIZATION
If you wish to designate authority to another individual or firm so that they may provide information on your
behalf, please complete this section.
J. Phillip Norris, P.E.
Designated agent (individual or firm): Norris, Kuske & Tunstall Consulting Engineers, Inc.
Mailing Address:
Qn9 Market Strppt
City: Wilmington State: NC Zip: 28401
Phone: [phone]
VIIL APPLICANT'S CERTIFICATION
Fax: [phone]
Bruce Shell, New Hanover County
1, (print or type name of person listed in General Information, item 2) Manager
Certify that the information included on this permit application form is, to the best of my knowledge, correct and
that the project will be constructed in conformance with the approved plans, that the required deed restrictions and
protective covenants will be recorded, and that the proposed project complies with the requirements of l 5A NCAC
2H.1000. —::7� .
Signature:
Date: 7 la - 6 ?
Form SWU-101 Version 3.99 Page 4 of 4

J. Phillip Norris, P.E
NORRIS, KUSKE & TUNSTALL John S. Tunstall, P.E. John A. Kuske, III, P.E.
James T. Pyrtle, P.E. Kent P. Harrell, P.E.
CONSULTING ENGINEERS, INC. James L. Lewis, Jr., P.E. J.A. Kuske, P.E.
902 Market Street • Wilmington, NC 28401-4733 • Phone [phone] • Fax [phone]
E-Mail: [e-mail]
LETTER OF TRANSMITTAL
To: Ms. Rhonda Hall
Date: April 7, 2008
Job No. 07044
NC DENR / Division Water Quality
subied: Murrayville Fire Station
127 Cardinal Drive Extension
New Hanover County
Wilmington, NC
28405-3845
WE ARE SENDING YOU VIA MAIL
® ATTACHED ❑ UNDER SEPARATE COVER
❑ SHOP DRAWINGS ❑ PRINTS ❑ TRACINGS
❑ SPECIFICATIONS ❑ DISKS ❑ COPY OF LETTER
❑
FAX TRANSMITTAL: NUMBER OF PAGES
INCLUDING THIS TRANSMITTAL
Call 910-287-5900 if you have any difficulty
receiving this message.
COPIES
DATE
NO.
DESCRIPTION
1
Page 4 of State Stormwater application
1
Page 1 of Wet Detension Supplement
1
Page 2 of Wet Detension Supplement
2
Sheet 2.0
2
Sheet 2.4
BY:
® AS REQUESTED
❑ FOR YOUR USE
❑ FOR REVIEW AND COMMENT ❑ FOR APPROVAL
❑ FOR BIDS DUE ❑ YOUR PRINTS LOANED TO US
REMARKS:
CC:
SIGNED Joseph K. Bland, El / neh
CONFIDENTIAL AND PRIVILEGED: Information contained in this document is privileged and confidential, intended for the sole use of the
addressee. If you are not the addressee or the person responsible for delivering it to the addressee you are hereby notified that any dissemination,
distribution or copying of this document is strictly prohibited. If you have received this document in error please immediately notify the sender and
return to the address above.

ANORRIS, KUSKE &TUNSTALL
CONSULTING ENGINEERS, INC.
January 17, 2008
Ms. Rhonda Hall, Environmental Engineer
NC DENR
Division of Water Quality
Water Quality Section
127 Cardinal Drive Extension
Wilmington, NC 28405-3845
Re: Murrayville Fire Station
New Hanover County
NKT Project No. 07044
Dear Ms. Hall:
J. Phillip Norris, P.E.
John A. Kuske, III, P.E.
John S. Tunstall, P.E.
J.A. Kuske, P.E. of Counsel
In response to your emailed comments on December 20, 2007, the following is offered:
1. The plans, calculations, and page 2 of the state permit application form have
been updated.
2. Pond elevations have been corrected.
Please contact us if you have any further questions or comments. Thank you for your
assistance on this project.
Sincerely,
NORRIS, KUSKE & TUNSTALL
CONSULTING ENGINEERS, INC.
Joseph K. Bland, E.I.
JKB/neh
07044 01-17-08 s-sw-response-Itr
RF=1 1V ED
RYt
JAN 2 2 2008
902 Market Street • Wilmington, NC 28401-4733 0 Phone: [phone] • Fax: [phone]

Date Design 902 Market Street Sheet
�'' NORRIS, KUSKE&TUNSTALL Wiimin fOn, NC 28401-4733
ll�.l I1/d AM CONSULTING ENGINEERS, INC. g Ot
Check Job For Job No.
�7�fi,i/f�co Sim/�'vw�L fi�'�G+Ifi1�OnS

NORRIS, KUSKE TUNSTALL 1/1712008
CONSULTING ENGINEERS, INC.
State Stornawater Calculations
Proiect: NHC Fire Station Murraysville
Drainage Basin:
Drainage Area, DA =
Impervious Area =
Pervious Area =
% Impervious, I =
Storage Volume Required (Simple Method):
Design Depth, D =
Normal Pool Elevation =
State Storage Pool Elevation =
Bottom Pool Elevation =
Runoff Volume, Rv =
Required Storage Volume =
Provided Storage Volume =
Required Surface Area:
Average Depth, Davg =
% Imp
Low 30.00
High 40.00
Low 30.00
High 40.00
Required Surface Area =
Provided Surface Area =
Drawdown Orifice:
Avg. Head =
Drawdown Time =
Internal Diameter =
Internal Diameter =
Drawdown Time =
Internal Diameter =
Intemal Diameter=
Avg Internal Diameter =
Design Orifice Diameter =
NKT No:
151,579i sf
51;141sf
100,438 sf
33.74 %
1 l) in
35 SA = 8 121., sf
"'''`" ` 35; SA= 8974'sf
.. .
0.354 intin Rv = 0.05 + 0.009*1
4,467 ft3 V = D/12 x Rv x DA
5,129 ft3 OKI
3.06 ft
SA/DA Avg Depth Proj % Imp SA/DA
3 3.50 33.74 3.37
4
3.5
4.5
SA/DA =
0.30 It
2 days
0.11 It
1.34 in
5 days
0.07 ft
0.85 in
1.09 in
1.25 in
3.00 33.74 3.87
3.81 90% TSS removal, no filter strip
5,777 sf
8,121 sf OKI
172,800 s
432,000 s
OKI
07044
H:\PROJECTS\2007\07044 Murrayville Fire Station\Calculations\07044 -6-23-07 w future imp: State Storrnwater Pond
Spreadsheet (Avg. Depth)

1/17/2008
Main Pond Volume (Excluding Forebay)
Pond Normal Pool Area
Bottom of Veg Shelf Pool Area
Bottom Pool Area
Normal Pool Elevation
Bottom of Veg Shelf Elevation
Bottom Pool Elevation
Normal Pool to Bottom Pond Volume
Forebay Volume (Excluding Main Pond)
Normal Forebay Pool Area
Bottom Forebay Area
Normal Pool Elevation
Bottom Forebay Elevation
Forebay Sizing
5,561 `
:!sf
2943 e sf
'sf
35
ft
rjZ3 '`?ft
25
"ft
17,035
FT'
2;316 . sf
177 i sf
35 It
Normal Pool to Bottom Forebay Volume 3,740 ft3
Percent Forebay Volume: 1 18.0% (18 - 22% Required) OKI
H:\PROJECTS\2007\07044 Murrayville Fire Station\Calculations\07044-8-23-07 w future imp.- State Stormwater
Pond Spreadsheet (Avg. Depth)

Stormwater Pond Average Death
Required Information
Elevation Normal Pool (Enp)
Elevation Bottom Vegetated Shelf (E,,)
Elevation Bottom Pool (Ebp)
Surface Area Normal Pool (A,,)
Surface Area Bottom Vegetated Shelf (A,,)
Surface Area Bottom Pool (Abp)
Weighted Average Method
35:00 ft
34 33 i ft
25 M ft
5561:'M sf
2942.00 sf
:�,98.001 sf
Area 1 (A,)
2619.00 sf
A,=A p kv
Depth 1 ( DI)
0.34 ft
Dj= (Eap-Ev,)/2
Area 2 (A2)
2844.00 sf
A2=A,,,-Abp
Depth 2 ( D2)
5.34 ft
D2= [(ESP E�j+(E,p-Ebp)]/2
Area 3 (A3)
98.00 sf
A3=Abp
Depth 3 ( D3)
10.00 ft
D3=E,PEbp
Da y==[F (Dn x A,)] / Anp
Davy 3.06 ft

NORRIS, KUSKE &TUNSTALL
CONSULTING ENGINEERS, INC.
October 4. 2007
Ms. Linda Lewis, Environmental Engineer
NC DENR / Division of Water Quality
Water Quality Section
127 Cardinal Drive Extension
Wilmington, NC 28405-3845
Re: State Stormwater Permit Submittal
Murrayville Fire Station
New Hanover County, NC
NKT Project No. 07044
Dear Ms. Lewis:
J. Phillip Norris, P.E.
John A. Kuske, III, P.E.
John S. Tunstall, P.E.
CA J.A. Kuske, P.E. of Counsel
8,
Enclosed are two (2) sets of plans for the subject project, two (2) drainage area plans,
one (1) set of calculations, one (1) copy of the stormwater narrative, the original
Division of Water Quality Stormwater Management Permit application, the original
SWU-102 supplement form and a $505.00 check for the permit review fee.
Please review this information for approval and contact us with any questions or
comments you may have. Thank you for your assistance on this project.
Sincerely,
NORRIS, KUSKE & TUNSTALL
CONSULTING ENGINEER , INC.
Phi I ANo, . E.
JPN/neh
07044 10-04-07-s-sw-Itr
Enclosures
cc: Donnie Hall / New Hanover County Fire Chief
Bruce Shell / New Hanover County Manager
902 Market Street • Wilmington, NC 28401-4733 • Phone: [phone] • Fax: [phone]

FDate I Design I 9Market Street
NORR15, KUSKE&TUNSTALL
I�1e \„i1 CONSULTING sNcineeas. INC. Wilmington, NC 28401-4733 Of
Check Job I For JoOlvo.
JPH I MuMt0M V'u .E 50�51Dw, o4' a�.cC 0-7�
1

777
Pre -Development
�SubcatR49chlon
\L� LLL�j YJ
22,
Post Develo ment ent
Ip
Stormwater Pond

07044 R1 Stormwater Pond
Prepared by {enter your company name here}
HvHrnr.AnA 7 10 %/n 000479 © 2005 HvdroCAD Sof
Murrayville Fire Station
Type // 24-hr 2 yr storm event Rainfall=4.50"
Page 2
LLC
Subcatchment 1S: Pre -Development
Runoff = 2.02 cfs @ 12.80 hrs, Volume= 0.337 af, Depth> 1.16"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 2 yr storm event Rainfall=4.50"
Area (ac) CN Description
3.501 65 Woods/grass comb., Fair, HSG B
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
31.5
100
0.0050
0.1
Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.50"
1.7
65
0.0154
0.6
Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
35.0
200
0.0154
0.1
Sheet Flow,
Woods: Lioht underbrush n= 0.400 P2= 4.50"
68.2 365 Total
Subcatchment 1S: Pre -Development
O Runoff
z Type II 24-hr 2 yr storm event
Rainfall=4.50"
Runoff Area=3.501 ac
Runoff Volume=0.337 of
Runoff Depth>116"
Flow Length=365'
LL Tc=68.2 min
CN=65
9 10 11 12 13 14 15 16 17 18
Time (hours)

07044 R1 Stormwater Pond
Prepared by {enter your company name
HvdroCADO 7.10 sin 000479 © 2005 HydroC
Murrayville Fire Station
Type 11 24-hr 2 yr storm event Rainfall=4.50"
Page 3
LLC
Subcatchment 2S: Post Development
Runoff = 5,91 cfs @ 12.27 hrs, Volume= 0.541 af, Depth> 1.86"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 2 yr storm event Rainfall=4.50"
Area (ac) CN Description
1,150 98 Paved parking, sidewalks, & roofs
1.930 65 Woods/grass comb., Fair, HSG B
0.411 61 >75% Grass cover, Good HSG B
3.491 75 Weighted Average
Tc Length Slope Velocity Capacity Description
31.5 250 0.0113 0.1 Sheet Flow,
Grass: Dense n= 0.240 P2= 4.50"
Subcatchment 2S: Post Development
6 Type II 24-hr 2 yr storm event
Rainfall=4.50"
5 Runoff Area=3.491'. ac
Runoff Volume=0.541 of
Q
Runoff Depth>1.86"
Flow Length=250'
a Tc=31.5 min
0 3
CN-75
2
1
5 6 7 8 9 10 11 12 13
Time (hours)
15 16 17 18 19 20
0 RunoH

07044 R1 Stormwater Pond
Prepared by {enter your company name here}
HAroCADO 7.10 s/n 000479 © 2005 HydroCAD Sof
Murrayville Fire Station
Type 1124-hr 2 yr storm event Rainfall=4.50"
Page 4
Pond 3P: Stormwater Pond
Inflow Area =
3.491 ac,
Inflow Depth > 1.86"
for 2 yr storm event event
Inflow =
5.91 cfs @
12.27 hrs, Volume=
0.541 of
Outflow =
1.96 cfs @
12.78 hrs, Volume=
0.406 af, Atten= 67%, Lag= 30.5 min
Primary =
1.96 cfs @
12.78 hrs, Volume=
0,406 of
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Peak Elev= 36.16' @ 12,78 hrs Surf.Area= 9,789 sf Storage= 10,353 cf
Plug -Flow detention time= 119.5 min calculated for 0.405 of (75% of inflow)
Center -of -Mass det. time= 58.9 min ( 871.3 - 812.4 )
Volume Invert
Avail Storage Storage Description
#1 35.00'
44,346 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
35.00
8,121
0 0
35.60
8,974
5,129 5,129
36.00
9,555
3,706 8,834
37.00
11,045
10,300 19,134
38.00
12,592
11,819 30,953
39.00
14,195
13,394 44,346
Device Routing
Invert
Outlet Devices
#1 Primary
35.00'
24.0" x 40.0' long Culvert Ke= 0.500
Outlet Invert= 34.90' S= 0.0025 7' Cc= 0.900
n= 0.012 Concrete pipe, finished
#2 Device 1
35,00'
1.2" Vert. Orifice/Grate C= 0.600
#3 Device 1
35.60'
2.10' W x 0.30' H Vert. Orifice/Grate C= 0.600
#4 Device 1
36.50'
1.20' W x 0.35' H Vert. Orifice/Grate C= 0.600
#5 Device 1
37.50'
4.00' x 4.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600
Primary OutFlow Max=1.96 cfs @ 12.78 hrs HW=36.16' (Free Discharge)
t- =Culvert (Passes 1.96 cfs of 4.64 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.04 cfs @ 5.1 fps)
3=Orifice/Grate (Orifice Controls 1.92 cfs @ 3.1 fps)
=Orifice/Grate ( Controls 0.00 cfs)
=Orifice/Grate ( Controls 0.00 cfs)

Murrayville Fire Station
07044 R1 Stormwater Pond Type /I 24-hr 2 yr storm event Rainfall=4.50"
Prepared by {enter your company name here} Page 5
HydroCADO 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
W
591
y_ Inflow Area=3.491 ac
Peak Elev=36.16'
3;
Storage__=_10,353 .cf
1�0.. 11 '12 13 14 15 16 17 15 19 20
Time (hours)
Pond 3P: Stormwater Pond
Stage -Discharge
Discharge (cfs)
io of ow
D Primary
D Primary

Murrayville Fire Station
07044 R1 Stormwater Pond Type /I 24-hr 2 yr storm event Rainfall=4.50"
Prepared by {enter your company name here} Page 6
HydroCADC 7 10 s/n 000479 C 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
Stage -Area -Storage
-5 Surface
10 Storage
Storage (cubic -feet)

Murrayville Fire Station
07044 R1 Stormwater Pond Type // 24-hr 10 yr storm event Rainfall=6.72"
Prepared by {enter your company name here} Page 7
HydroCAD®7 10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Subcatchment 1S: Pre -Development
Runoff = 4.76 cfs @ 12.77 hrs, Volume= 0.750 at, Depth> 2.57"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 10 yr storm event Rainfall=6.72"
Area (ac) CN Description
3.501 65 Woods/grass comb., Fair, HSG B
Tc Length Slope Velocity Capacity Description
31.5 100 0.0050 0.1 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.50"
1.7 65 0,0154 0.6 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
35.0 200 0.0154 0.1 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.5_0"
68.2 365 Total
Subcatchment 1 S: Pre -Development
Hydrograph
- - - - I ❑ Runaff
Type II 24-hr 10 yr storm event
Rainfall=6..72" ;
4 Runoff Area=3.501 ac'
Runoff Volume=0.750 of
Runoff Depth>2.57"
3-
Flow Length=365'
Tc=68.2 min
CN=65 --- - —_
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Time (hours)

07044 R1 Stormwater Pond
Prepared by {enter your company name
HvdroCAD® 7.10 s/n 000479 © 2005 HydroC.
Murrayville Fire Station
Type/1 24-hr 10 yr storm event Rainfall=6.72"
Page 8
7nznnrrr
Subcatchment 2S: Post Development
Runoff = 11.42 cfs @ 12.26 hrs, Volume= 1.043 af, Depth> 3.59"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 10 yr storm event Rainfall=6.72"
Area (ac) CN Description
1,150 98 Paved parking, sidewalks, & roofs
1.930 65 Woods/grass comb., Fair, HSG B
0.411 61 >75% Grass cover, Good, HSG B
3.491 75 Weighted Average
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
31.5 250 0,0113 0.1 Sheet Flow,
Grass: Dense n= 0.240 P2= 4.50"
Subcatchment 2S: Post Development
Hydrograph
_ . '- " _ .. .. _ _ _ _ _ -
❑ Runoff
12-
naz tle
Type II 24-hr 10 yr storm event
Rainfall=6.72"
0
s Runoff-Area=3.491 ac
9
Runoff Volume=1.043..af.
e
Runoff Depth>3.59"
Flow Length=250'
Tc=31.5 min
o s
LL
CN=75
s

Murrayville Fire Station
07044 R1 Stormwater Pond Type 1124-hr 10 yr storm event Rainfall=6.72"
Prepared by {enter your company name here) Page 9
HydroCAD®7 10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
Inflow Area =
3.491 ac,
Inflow Depth > 3.59"
for 10 yr storm event event
Inflow =
11.42 cfs @
12.26 hrs, Volume=
1.043 of
Outflow =
4.55 cfs @
12.68 hrs, Volume=
0.900 af, Atten= 60%, Lag= 25.1 min
Primary =
4.55 cfs @
12.68 hrs, Volume=
0.900 of
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Peak Elev= 36.99' @ 12.68 hrs Surf.Area= 11,031 sf Storage= 19,029 cf
Plug -Flow detention time= 95.6 min calculated for 0.897 of (86% of inflow)
Center -of -Mass det. time= 54.9 min ( 853.6 - 798.7 )
Volume Invert
Avail Storage Storage Description
#1 35.00'
44,346 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surl
Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
35.00
8,121
0 0
35.60
8,974
5,129 5,129
36.00
9,555
3,706 8,834
37.00
11,045
10,300 19,134
38.00
12,592
11,819 30,953
39.00
14,195
13,394 44,346
Device Routing
Invert
Outlet Devices
#1 Primary
35.00'
24.0" x 40.0' long Culvert Ke= 0.500
Outlet Invert= 34.90' S= 0.00257 Cc= 0.900
n= 0.012 Concrete pipe, finished
#2 Device 1
35.00'
1.2" Vert. Orifice/Grate C= 0.600
#3 Device 1
35.60'
2.10' W x 0.30' H Vert. Orifice/Grate C= 0.600
#4 Device 1
36.50'
1.20' W x 0.35' H Vert. Orifice/Grate C= 0.600
#5 Device 1
37.50'
4.00' x 4.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600
Primary OutFlow Max=4.55 cfs @ 12.68 hrs HW=36.99' (Free Discharge)
L1=Culvert (Passes 4.55 cfs of 11.52 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.05 cfs @ 6.7 fps)
3=Orifice/Grate (Orifice Controls 3.38 cfs @ 5.4 fps)
=Orifice/Grate (Orifice Controls 1.12 cfs @ 2.7 fps)
=Orifice/Grate ( Controls 0.00 cfs)

Murrayville Fire Station
07044 R1 Stormwater Pond Type ll 24-hr 10 yr storm event Rainfall=6.72"
Prepared by tenter your company name here} Page 10
HydroCAD®7 10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
Hydrograph
. _.. _.. _ ..
a Inflow
n sa ds
❑ Primary
12
Inflow Area=3.491 ac
"
Peak Elev=36.9,9'
10
- _ . - Storage=! 9,029-cf -
g
y
LL
5
155 cb
4
3
W
Time (hours)
Pond 3P: Stormwater Pond
Staae-Discharge
Discharge (cfs)
D Primary

Murrayville Fire Station
07044 R1 Stormwater Pond Type // 24-hr 10 yr storm event Rainfall=6.72"
Prepared by {enter your company name here} Page 11
HydroCAD®7 10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
Stage -Area -Storage
0 Surface
0 Storage
Storage (cubic -feet)

07044 R1 Stormwater Pond
Prepared by {enter your company name. here}
HvHrncAnR 7 10 s/n 000479 (9 2005 HvdroCAD Sof
Murrayville Fire Station
Type 1124-hr 25 yr storm event Rainfall=& 01 "
Page 12
Subcatchment 1S: Pre -Development
Runoff = 6.54 cfs @ 12.75 hrs, Volume= 1.021 af, Depth> 3.50"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 25 yr storm event Rainfall=8.01"
Area (ac) CN Description
3.501 65 Woods/grass comb., Fair, HSG B
Tc Length Slope Velocity Ca
min) (feet) (ft/ft) (ft/sec)
Description
31.5 100 0.0050 0.1 Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4,50"
1.7 65 0.0154 0.6 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
35.0 200 0.0154 0.1 Sheet Flow,
Woods: Lioht underbrush n= 0.400 P2= 4.50"
68.2 365 Total
Subcatchment 1S: Pre -Development
Hydrograph
❑ Runoff
6.YI Ci6
Type II 24-hr 25 yr storm event
s Rainfall=8.01"
3,
Runoff Area=3.501 ac `>
5 Runoff Volume=1.021 of
Runoff Depth>3.50"
4 Flow Length=365'
Tc=68.2 min
3 CN=65
2
1
o..
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Time (hours)

Murrayville Fire Station
07044 R1 Stormwater Pond Type Il24-hr25 yrstorm event Rainfall=& 01 "
Prepared by {enter your company name here} Page 13
HydroCADO 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Subcatchment 2S: Post Development
Runoff = 14.77 cfs @ 12.26 hrs, Volume= 1.356 af, Depth> 4.66"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 25 yr storm event Rainfall=8.01"
Area (ac) CN Description
1.150
98
Paved parking, sidewalks, & roofs
1.930
65
Woods/grass comb., Fair, HSG B
0.411
61
>75% Grass cover, Good, HSG B
3.491
75
Weighted Average
Tc
Length
Slope
min)
(feet)
(f /ft)
31.5
250
0.0113
Capacity Description
0.1 Sheet Flow,
Grass: Dense n= 0.240 P2= 4.50"
Subcatchment 2S: Post Development
Hydrograph
147 de
15 Type II 24-hr25 yrstorm event
0 Rainfall=8.01"
13- `y�`
t2 Runoff Volume 3.491 ac
Runoff Area-
_. ,1.356 of
11_
10. f.. Runoff Depth>4.66"
Flow Len6th=250'
a'< Tc=31.5 min
LL 7 CN=75
6 r
4
3
2.
1
0. . .
6 6 7 6 9 10 11 12 13 14 15 i6 17 18 19 20
Time (hours)
❑ Runoff

Murrayville Fire Station
07044 R1 Stormwater Pond Type 1124-hr 25 yr storm event Rainfall=& 01 "
Prepared by {enter your company name here} Page 14
HydroCADS 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
Inflow Area =
3.491 ac,
Inflow Depth > 4.66"
for 25 yr storm event event
Inflow =
14.77 cfs @
12.26 hrs, Volume=
1.356 of
Outflow =
5.82 cfs @
12.68 hrs, Volume=
1.208 af, Atten= 61 %, Lag= 25.1 min
Primary =
5.82 cfs @
12.68 hrs, Volume=
1.208 of
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Peak Elev= 37.46' @ 12.68 hrs Surf.Area= 11,763 sf Storage= 24,424 cf
Plug -Flow detention time= 90.5 min calculated for 1.208 of (89% of inflow)
Center -of -Mass det. time= 55.8 min ( 848.8 - 793.0 )
Volume Invert
Avail Storage Storage Description
#1 35.00'
44,346 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
35.00
8,121
0 0
35.60
8,974
5,129 5,129
36.00
9,555
3,706 8,834
37.00
11,045
10,300 19,134
38.00
12,592
11,819 30,953
39.00
14,195
13,394 44,346
Device Routing
Invert
Outlet Devices
#1 Primary
35.00'
24.0" x 40.0' long Culvert Ke= 0.500
Outlet Invert= 34,90' S= 0.0025'/' Cc= 0,900
n= 0.012 Concrete pipe, finished
#2 Device 1
35.00'
1.2" Vert. Orifice/Grate C= 0.600
#3 Device 1
35.60'
2.10' W x 0.30' H Vert. Orifice/Grate C= 0.600
#4 Device 1
36.50'
1.20' W x 0.35' H Vert. Orifice/Grate C= 0.600
#5 Device 1
37.50'
4.00' x 4.00' Horiz. Orifice/Grate Limited to weir flow C= 0,600
Primary OutFlow Max=5.82 cfs @ 12.68 hrs HW=37.46' (Free Discharge)
t- =Culvert (Passes 5.82 cfs of 15.16 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.06 cfs @ 7.5 fps)
3=Orifice/Grate (Orifice Controls 3.97 cfs @ 6.3 fps)
=Orifice/Grate (Orifice Controls 1.79 cfs @ 4.3 fps)
=Orifice/Grate ( Controls 0.00 cfs)

Murrayville Fire Station
07044 R1 Stormwater Pond Type lI 24-hr 25 yr storm event Rainfall=& 01 "
Prepared by {enter your company name here} Page 15
HydroCAD®7 10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
13
12
1,
10-
`0 9
3 8
0
n 7
6-
-
W
567861'01'11213
Time (hours�
0 Inflow
0 Primary
Inflow Area=3.491 ac
Peak Elev=37.46'
Storage24,4
=24 cf.
15 16 17 18 19 20
Pond 3P: Stormwater Pond
Staqe-Discharge
Discharge (cts)
0 Primary

07044 R1 Stormwater Pond
Prepared by {enter your company name here}
HvdroCAD® 7.10 s/n 000479 © 2005 HydroCAD Sof
W
Murrayville Fire Station
Type 1124-hr 25 yr storm event Rainfall=8.01 "
Page 16
Pond 3P: Stormwater Pond
Stage -Area -Storage
S:�rtacelRcrize:�_'�-!M`et:ed
Storage (tunic -reed
Surface
❑ Storage

07044 R1 Stormwater Pond
Prepared by {enter your company name
HvdrnCAD® 7.10 s/n 000479 © 2005 HydroC,
Murrayville Fire Station
Type It 24-hr 100 yr storm event Rainfall=10.00"
Page 17
s LLC
Subcatchment 1S: Pre -Development
Runoff = 9.44 cfs @ 12.73 hrs, Volume= 1.467 af, Depth> 5.03"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type It 24-hr 100 yr storm event Rainfall=10.00"
Area (ac) CN Description
3.501 65 Woods/grass comb., Fair, HSG B
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(f /sec)
(cfs)
31.5
100
0.0050
0.1
Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.50"
1.7
65
0.0154
0.6
Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
35.0
200
0.0154
0.1
Sheet Flow,
Woods: Licht underbrush n= 0.400 P2= 4.50"
68.2 365 Total
Subcatchment 1S: Pre -Development
Hydrograph
Type 1124-hr.100 yr storm event
9 Rainfall.=10.00 _: ..._
8 Runoff Area=3.501 ac
7 RunoffV6lume=1.467 af- --
Runoff Depth>5.03"
6-
Flow Length=365'
u
5 Tc=68.2 min
CN=65- . .
Time (houm)

Murrayville Fire Station
07044 R1 Stormwater Pond Type 11 24-hr 100 yr storm event Rainfall=10.00"
Prepared by {enter your company name here} Page 18
HydroCAD®7 10 s/n 000479 @ 2005 HydroCAD Software Solutions LLC 7/23/2007
Subcatchment 2S: Post Development
Runoff = 20.02 cfs @ 12.26 hrs, Volume= 1.854 af, Depth> 6.37"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 100 yr storm event Rainfall=10.00"
Area (ac) CN Description
1.150 98 Paved parking, sidewalks, & roofs
1.930 65 Woods/grass comb., Fair, HSG B
0.411 61 >75% Grass cover, Good, HSG B
3.491 75 Weighted Average
Tc Length Slope Velocity Capacity Description
31.5 250 0.0113 0.1 Sheet Flow,
Grass: Dense n= 0.240 P2= 4.50"
Subcatchment 2S: Post Development
21.
L
20
.. . _... .. _ -.. .... . .. ..
19
18
-
17 .
..__ .. ..... ..._._
6
-Type II 24-hr 100 yr storm event -
_Rainfall=10.00"
-Runoff-Area=3.491 ac
Runoff Volume=1.854.af
Runoff Depth>6.37"
Flow Length=250' ..
Tc 31.5 min
CN=75 .
Yi p
/���✓'III//I///////////////////////
567861,011121314151617181920
Time (houm)

Murrayville Fire Station
07044 R1 Stormwater Pond Type/1 24-hr 100 yr storm event Rainfall=10.00"
Prepared by {enter your company name here} Page 19
HydroCAD& 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 7/23/2007
Pond 3P: Stormwater Pond
Inflow Area =
3.491 ac,
Inflow Depth > 6.37"
for 100 yr storm event event
Inflow =
20.02 cfs @
12.26 hrs, Volume=
1.854 of
Outflow =
14.16 cfs @
12.47 hrs, Volume=
1.701 af, Atten= 29%, Lag= 12.8 min
Primary =
14.16 cfs @
12.47 hrs, Volume=
1.701 of
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Peak Elev= 37.78' @ 12.47 hrs Surf.Area= 12,248 sf Storage= 28,191 cf
Plug -Flow detention time= 78.9 min calculated for 1.701 of (92% of inflow)
Center -of -Mass det. time= 50.9 min ( 836.8 - 785.9 )
Volume Invert
Avail Storage Storage Description
#1 35.00'
44,346 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
35.00
8,121
0 0
35.60
8,974
5,129 5,129
36.00
9,555
3,706 8,834
37.00
11,045
10,300 19,134
38.00
12,592
11,819 30,953
39.00
14,195
13,394 44,346
Device Routing
Invert
Outlet Devices
#1 Primary
35.00'
24.0" x 40.0' long Culvert Ke= 0.500
Outlet Invert= 34.90' S= 0.0025 T Cc= 0.900
n= 0.012 Concrete pipe, finished
#2 Device 1
35.00'
1.2" Vert. Orifice/Grate C= 0.600
#3 Device 1
35.60'
2.10' W x 0.30' H Vert. Orifice/Grate C= 0.600
#4 Device 1
36.50'
1.20' W x 0.35' H Vert. Orifice/Grate C= 0.600
#5 Device 1
37.50'
4.00' x 4.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600
Primary OutFlow Max=13.96 cfs @ 12.47 hrs HW=37.77' (Free Discharge)
t1=Culvert (Passes 13.96 cfs of 16.98 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.06 cfs @ 7.9 fps)
3=Orifice/Grate (Orifice Controls 4.31 cfs @ 6.8 fps)
=Orifice/Grate (Orifice Controls 2.12 cfs @ 5.0 fps)
=Orifice/Grate (Weir Controls 7.47 cfs @ 1.7 fps)

Murrayville Fire Station
07044 R1 Stormwater Pond Type // 24-hr 100 yrstorm event Rainfall= 10. 00"
Prepared by {enter your company name here} Page 20
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07044 R1 Stormwater Pond
Prepared by {enter your company name
Murrayville Fire Station
Type 11 24-hr 100 yrstorm event Rainfall= 10. 00"
Page 21
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STORMWATER SYSTEM & EROSION CONTROL NARRATIVE
NEW HANOVER COUNTY. NORTH CAROLINA
For
New Hanover County Murrayville Fire Station
230 Government Center Drive, Suite 130
Wilmington, NC 28403
[phone]
October 2007
Prepared by:
NORRIS, KUSKE & TUNSTALL CONSULTING ENGINEERS, INC.
902 Market Street
Wilmington, North Carolina 28401
[phone]
[phone] (Fax)
NKT Project No. 07044

NARRATIVE
DESCRIPTION:
The project site is a 3.5 acre tract located in New Hanover County along
Murrayville Road. The soils of the site consist of lightly vegetated - moderately wooded
- sandy topsoil and grades ranging from 0% to 2%. Approximately 3.1 acres will be
graded to allow construction of a Fire Station with paved parking and paved access.
The runoff from the site is estimated using the rational method 10-year design storm
and rainfall data for the area. Construction is scheduled to begin as soon as all permits
and approvals are obtained.
The project consists of a lightly wooded tract to be developed into a New
Hanover County Fire Station. Approximately 3.1 acres will be disturbed and 1.18 acres
(37%) will be covered by impervious surfaces.
EROSION CONTROL MEASURES:
The attached plans and specifications outline the requirements for erosion
control measures. Silt fencing will be provided along each side of the entrance drive
where stormwater would be expected to sheet flow from disturbed areas directly to
adjacent property. Gravel check dams will not be provided unless the Contractor has to
temporarily discharge into an open ditch instead of the proposed storm drain outfall.
The detention pond will be used as a silt basin during construction and restored to its
design contours prior to completion. A gravel construction entrance will be constructed
at the eastern entrance. Maintenance will be provided by the grading contractor and
developer.
STORMWATER MANAGEMENT MEASURES:
The project site is located in New Hanover County. Land disturbing on the site
will exceed one acre, which requires the site to comply with both State and County
Regulations. The stormwater runoff from the development will be directed to the
stormwater detention pond. The stormwater detention pond was designed to
accommodate this site at 37% impervious area lot coverage.
CONSTRUCTION SEQUENCE:
The Contractor will install the gravel construction entrance and silt fence prior to
beginning any clearing and grading operations. Additional silt fence will be installed
when and if conditions warrant during construction. The detention pond/silt basin will

be constructed immediately after that portion of the site is cleared, and outlet structure
with protection will be installed. Disturbed areas will be landscaped or seeded upon
completion.

EROSION CONTROL NOTES AND MAINTENANCE PLAN
1. Install erosion control measures before beginning construction or as soon
thereafter as possible. All erosion and sediment control practices will be
checked for stability and operation following every runoff -producing rainfall but in
no case less than once every week. Any needed repairs will be made
immediately to maintain all practices as designed.
2. Maintain the gravel construction entrances in a condition to prevent mud or
sediment from leaving the construction site. The contractor shall inspect the
construction entrances on a daily basis. This will require periodic top dressing
with additional No. 4 stone. Any objectionable materials spilled, washed, or
tracked onto public roadways shall be removed immediately.
3. Install erosion control measures around the drop inlets as shown on the plans to
trap silt during construction. Inspect the erosion control around the inlets after
each rain and make repairs immediately. Remove sediment when it becomes 8"
deep to provide adequate storage volume for subsequent rains. Remove and
replace the rock when it no longer drains properly. When the contributing
drainage area has been adequately stabilized, remove all materials and any
unstable soil and either salvage or dispose of it properly. Bring the disturbed
area to proper grade and appropriately stabilize all bare areas around the drop
inlets.
4. Sediment will be removed from behind the silt fence when it becomes 0.5 feet
deep at the fence. The sediment fence will be repaired as necessary to maintain
a barrier. Silt fence stakes shall be spaced 6 feet apart unless a wire backing is
used with 8 foot stake spacing.
5. Inspect temporary sediment traps / check dams after each period of significant
rainfall. Remove sediment and restore the trap to its original dimensions when
the sediment has accumulated to one-half the design depth of the trap. Place
the sediment that is removed in the designated disposal area and replace the
contaminated part of the gravel facing. Check the structure for damage from
erosion or piping. Periodically check the depth of the spillway to ensure it is a
minimum of 1.5 ft below the low point of the embankment. Immediately fill any
settlement of the embankment to slightly above design grade. Any riprap
displaced from the spillway must be replaced immediately. After all sediment -
producing areas have been permanently stabilized, remove the structure and all
unstable sediment. Smooth the area to blend with the adjoining areas and
stabilize properly.
6. The stormwater pond will act as a sediment basin and will be cleaned out when
the level of sediment reaches 2.0 ft below the top of the riser. Gravel will be
cleaned or replaced when the sediment pool no longer drains properly.

7. The angle for graded slopes and fills shall be no greater than the angle that can
be retained by vegetative cover or other adequate erosion -control devices or
structures. In any event, slopes left exposed will, within 21 calendar days of
completion of any phase of grading, be planted or otherwise provided with
temporary or permanent ground cover, devices, or structures sufficient to restrain
erosion.
8. All disturbed areas shall be seeded within 21 calendar days of disturbance. All
seeded areas will be fertilized, reseeded as necessary and mulched according to
specifications in the vegetative plan to maintain a vigorous, dense vegetative
cover.
9. More stringent measures shall be used to halt erosion if those shown on this plan
are not effective.
10. All erosion shall be controlled including side slopes before the project is
completed.
11. Remove temporary measures upon completion of project. All permanent
measures will be well established before project closeout.

SECTION 02920
SOIL EROSION AND SEDIMENTATION CONTROL
1. GENERAL
1.1 Contractor shall take every reasonable precaution throughout construction to
prevent the erosion of soil and the sedimentation of streams, lakes, reservoirs, other
water impoundments, ground surfaces, or other property as required by State and Local
regulations.
1.2 The Contractor shall install all required silt fences, and construction entrances at
the initiation of work, and have these measures reviewed and approved by the local
permit authority prior to clearing and grading operations.
1.3 The Contractor shall, within 21 days of suspension or completion of land
disturbing activities, provide permanent protective covering for disturbed areas.
Temporary and permanent erosion control measures shall be coordinated to assure
economical, effective, and continuous erosion and siltation control throughout the
construction and post -construction period. Use the specified seed for both temporary and
permanent seeding.
2. PRODUCTS
2.1 Asphalt for anchoring mulch shall be Type SS-1 Emulsion.
2.2 Fertilizer shall be 10-10-10 grade or equivalent.
2.3 Lime shall be dolomitic agricultural ground limestone containing not less than 10
percent magnesium oxide.
2.4 Mulch shall be small grain straw, hay, wood chips, asphalt emulsion, jute or other
suitable material free of undesirable weed seed.
2.5 Phosphate shall be 20 percent superphosphate or equivalent.
2.6 Seed shall be 20% carpet grass, 24% Bermuda, 20% turf Fescue, 10% Creeping
Red Fescue, and 24% Annual Rye grain. Bermuda seed shall be hulled for warm
weather planting and unhulled for cool weather planting. Purity of seed shall be a
minimum of 98 percent and germination shall be a minimum of 85 percent.
2.7 Silt fence shall consist of NCDOT Class A fabric supported by metal posts
spaced not more than 6 feet on center. The bottom of the fabric shall be buried a
minimum of 6 inches.
2.8 Gravel for check dams shall be #57 washed stone.

2.9 Aggregate for construction entrance shall be #4 washed stone.
2.10 Stone rip rap for check dams and erosion control shall be NCDOT Class A or B
as shown.
3. EXECUTION
3.1 General: Take every practicable measure during construction or suspension to
work to minimize erosion and siltation. Measures should include good construction
practices, temporary physical barriers to sediment travel, settling basins for new ditches,
and establishment of vegetative cover.
3.2 Construction Practices
3.2.1 Avoid dumping soil or sediment into any wetland or watercourse.
3.2.2 Maintain an undisturbed vegetative buffer where possible between a natural
watercourse and trenching and grading operations.
3.2.3 Avoid equipment crossings of streams, creeks, and ditches where practicable.
3.2.4 Grade all cut, fill and ditch slopes to minimum slope of 3:1, unless otherwise
shown or directed.
3.3 Temporary Physical Barriers are required where sedimentation on off site
property or excessive erosion is a problem.
3.3.1 Mulch shall be used for temporary stabilization of areas subject to excessive
erosion and for protection of seedbeds after planting where required.
1. Apply grain straw and hay at a rate of 75 to 100 pounds per 1000 square feet
and wood chips at a rate of 500 pounds per 1000 square feet. Jute and mesh
should be installed as per manufacturer's instructions.
2. Asphalt emulsion for slope stabilization should be applied at a rate of 1,000
gallons per acre. Asphalt emulsion used for anchoring straw should be
applied at a rate of 150 gallons per ton of straw.
3.3.2 Silt Fences shall be used at the base of slopes to restrict movement of sediment
from the site. Clean silt fence of accumulated sediment after each rainfall event or
when it exceeds a depth of 0.5 feet above natural grade.
3.3.3 Stone Check Dams, placed at the discharges of creeks, ditches, and swales,
shall consist of Class A or Class B erosion control stone at minimum two feet high and

three feet thick across the watercourse, with a one foot thick layer of gravel on upstream
side. Remove sediment if accumulated to a depth of 1.0 feet at upstream face.
3.4 Vegetative Cover: Establish and maintain permanent vegetative cover on all
unpaved areas disturbed by the work.
3.4.1 Preparation of Seedbed: Areas to be seeded shall be scarified to a depth of 4
inches and until a firm, well pulverized, uniform seedbed is prepared. Lime, phosphorous
and fertilizer shall be applied during the scarification process in accordance with the
following rates:
Lime: 45 pounds per 1000 square feet
Phosphorous: 20 pounds per 1000 square feet
Fertilizer: 17 pounds per 1000 square feet
3.4.2 Seeding: Disturbed areas shall be seeded with 2 to 3 pounds per 1000 square
feet of the specified seed mixture. Seed shall be worked into the bed to a depth of 1/4
inch. Regrade and seed eroded areas immediately
3.4.3 Mulch all areas immediately after seeding. Mulch shall be applied and anchored
as specified hereinbefore. Reapply as necessary to retain cover until grass is
established.
3.5 Construction Entrance: Provide an aggregate drive, 20 feet wide by 50 feet long
by 6 inches thick at each entrance to the site used by construction vehicles, until such
time as the permanent roadway is constructed. Remove soil if accumulated to a depth
greater than 0.5 inches.
3.6 Maintenance: The Owner and Contractor shall be responsible for maintaining all
temporary and permanent erosion control measures. Temporary structures shall be
maintained until such time as vegetation is firmly established in the area protected by
the structure. Permanent streambank protection and grassed areas shall be
maintained until completion of the project. Areas that fail to show a suitable stand of
grass or which are damaged by erosion shall be immediately repaired.
END OF SECTION