HomeMy WebLinkAboutSW8050110_COMPLIANCE_20120202STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT
SW KZ
NO.
DOC TYPE
❑CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
YYYYMMDD
.Compliance Inspection Report
Permit: SW8050110 Effective: 02/02/05 Expiration: 02/02/15 Owner: Biltmore Developers, LLC
Project: Biltmore Developers
County: New Hanover 4614 Market St
Region: Wilmington
Wilmington NC 28405
Contact Person: J Allen Jordan Title: Phone: 910-693-1700
Directions to Project:
1.08 miles west from the intersection of Hwy 17 (Market St.) and 1-40 (College Rd.).
Type of Project: State Stormwater - HD - Detention Pond
Drain Areas: 1 -
On -Site Representative(s):
Related Permits:
Inspection Date: 02/18/2010 Entry Time: 01:30 PM
Primary Inspector: David W Cox
Secondary Inspector(s):
Reason for Inspection: Routine
Permit Inspection Type: State Stormwater
Facility Status: ❑ Compliant ■ Not Compliant
Question Areas:
State Stormwater
(See attachment summary)
Exit.Time: 02:00 PM
Phone: 910-796-7215
Inspection Type: Compliance Evaluation
Page: 1
Permit: SW8050110 Owner - Project: Biltmore Developers, I.LC
Inspection Date: 02/18/2010 Inspection Type: Compliance Evaluation Reason for Visit: Routine
Inspection Summary:
In order to bring this stormwater system into compliance you must provide the following:
1. Provide the required Engineer's Certificate.
File Review
Is the permit active?
Signed copy or the Engineer's certification is in the file?
Signed copy or the Operation & Maintenance Agreement is in the file?
Copy of the recorded deed restrictions is in the file?
Comment: 1. No Engineer's Certification in the file.
Yes No NA NE
Page: 2
N KT #04177
Permit No. 5ZAJ �'0 l I b
State of North Carolina (to he provided by DWQ)
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopied for use as an original
DWQ Stormwater Management Plan Review:
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
1. PROTECT INFORMATION
Project Name: Biltmore Developers — 4614 Market Street ^
Contact Person: J. Allen Jordan, Jr. Phone Number:
For projects with multiple basins, specify which basin this worksheet applies to:
elevations
Basin Bottom Elevation 91.0
Permanent Pool Elevation 94.5
Temporary Pool Elevation 95.5
areas
�(910) 693-1700
1
ft. (floor of the basin)
ft. (elevation of the orifices)
ft. (elevation of the discharge structure overflow)
Permanent Pool Surface Area 4,860 sq. ft.
Drainage Area 1.26 ac.
Impervious Area
volumes
1.26� ac
(water surface area at the orifice elevation)
(on -site and off -site drainage to the basin)
(on -site and of -site drainage to the basin)
Permanent Pool Volume 8,593 cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 8,160 cu. ft. (volume detained above the permanent pool)
Forebay Volume 1,796 cu. ft. (approximately 20% of total volume)
Other parameters
SA1DA' 8.0 (surface area to drainage area ratio from DWQ table)
Diameter of Orifice 1 in. (2 to 5 day temporary pool draw -down required)
Design Rainfall 1 in.
Design TSS Removal 2 90 % (minimum 85% required)
Form SWU-102 Version 3.99 Page 1 of 4
Footnotes:
When using the Division SA/DA tables, the correct SAIDA ratio for penmanent pool sizing should be computed based upon the
actual impervious % and permanent pool depth. Linear interpolation should be employed to determine the correct value for non-
standard table entries.
2. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90%TSS removal. The NCDENR BMP manual provides design tables for both 85% TSS removal and 90% TSS removal.
11. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Storrwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
nla
a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
b. The forebay volume is approximately equal to 20% of the basin volume.
c. The temporary pool controls runoff from the design storm event.
d. The temporary pool draws down in 2 to 5 days.
e. If required, a 30-foot vegetative filter is provided at the outlet (include non -erosive flow
calculations.
.� 1'. The basin length to width ratio is greater than 3: 1.
g. The basin side slopes above the permanent pool are no steeper than 3: 1.
h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
i. Vegetative cover above the permanent pool elevation is specified.
J. A trash rack or similar device is provided for both the overflow and orifice.
k. A recorded drainage easement is provided for each basin including access to nearest right-
of-way.
1. If the basin is used for sediment and erosion control during construction, clean out of the
basin is specified prior to use as a wet detention basin.
m. A mechanism is specified which will drain the basin for maintenance or an emergency.
c� Portable pump
111. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one) ❑ does
This system (check one) ❑ does
Form SWU-102 Version 3.99
® does not incorporate a vegetated filter at the outlet.
® does not incorporate pretreatment other than a forebay.
Page 2 of 4
Maintenance activities shall be performed as follows:
After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re -seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e.
stockpiling near a wet detention basin or stream, etc.)
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 3 feet in the main pond, the sediment shall be removed.
When the permanent pool depth reads
Sediment Re %Elvation
al EI. 92.'1 7
Bottom 92.25
FORF,BAY
1.69 feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 94.5
Sediment Removal Elevation 91.5 75%
Bottom Elevation 91.0 125
MAIN POND
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through
the emergency drain shall be minimized to the maximum extent practical.
Form SWU-102 Version 3.99 Page 3 of 4
7. A]I components of the wet detention basin system steal I be maintained in good working order.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: J. Allen Jordan, Jr
Title: Manner
Address: 275 S. Bennett Street, Sourthern Pines, NC 28387
Phone: (910) 693-1700
Signature:
Date
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and
a resident of the subdivision has been named the president.
I �%%�' �C.�iCI,[�/,cxj/,�s r� , a Notary Public for the State of
County of /�lGo��� , do hereby certify that �11e/) ✓Q,z,J rQ1
Personally appeared before me this,? day of fjP_.C_ „ �= and acknowledge the due
Execution of the foregoing wet detention basin maintenance requirements. Witness my hand and official seal.
VEMILUMM
�r O .
gnd•.
n r .
Signature
My commission expires 9
Form SWU-102 Version 3.99 Page 4 of 4
DETENTION POND ANALYSIS FILENAME: 050110-1
PROJECT #: SW8 050110-1 REVIEWER: P. Bartlett
PROJECT NAME: Biltmore Developers, 4614 Market St., Wilmington
DATE: 26-Jan-05
Receiving Stream: Burnt Mill Creek,/ Class: CSW,,--
Drainage Basin: Cape Fear Index No. 18-74-63-2
Site Area 1.26 acres
Drainage Area 4 square feet Area = 1.26 acres
IMPERVIOUS AREAS
On -site bldgs
On -site streets & parking
On -site sidewalks
TOTAL
SURFACE AREA CALCULATION
% IMPERVIOUS 78.75%�✓
Des. Depth 3.5-/
TSS.- 90V/
10800.00 square feet
31000.00 square feet
1425.00 square feet
'square feet
square feet
square feet
square feet
Rational C
0.95
0.95
0.95
11110GRIEZIM156 am.
SA/DA Ratio 7.88% --'
Req. SA 4323 sf
Prov. SA 48p sf
VOLUME CALCULATION * place a "l " in the box if Rational is used
Rational ?* 1 ✓ FOREBAY
Des. Storm i 10Q€inches Perm. Pool Volume= 8� �93 l
Rv= 0,76 Req. Forebay Volume= 1 TT8.6
Bottom 91 msl ✓ Provided Volume= 1796.00
Perm. Pool msl Percent=
Design Pool 95.5 msl ✓
Design SA 6020 sf
Req. Volume cf SA @
Prov. Volume 6:,7 cf Z Elevation=
ORIFICE CALCULATION
Avg. Head =
0.48 ft
Q2 Area =
0.90
sq. in.
Flow Q2, cfs
0.021xcfs
Q5 Area =
0.36
sq. in.
Flow Q5, cfs.
No. of Orifices
0.008,cf
✓Q=
Orifice Area
0.79
0.018
sq. in.
cfs
iDameter, inches
weir H x W
in
X
in
Drawdown
days
COMMENTS
Surface Area , Volume and Orifice are within Design Guideline:
WC S1:F0 t4 D` 0 0, JXm
STORMWATER SYSTEM & EROSION CONTROL NARRATIVE
BILTMORE DEVELOPERS
4614 Market Street
WILMINGTON, NORTH CAROLINA
For
Biltmore Developers, LLC
275 S. Bennett Street
Southern Pines, NC 28387
(910) 693-1700
January 2005
Prepared by:
NORRIS, KUSKE, & TUNSTALL
CONSULTING ENGINEERS, INC.
902 Market Street
Wilmington, North Carolina 28401
(910) 343-9653
(910) 343-9604 (Fax)
E-mail: office A- n kte n_q. com
NKT Project No. 04177
NKT Project No. 04177
NARRATIVE
DESCRIPTION:
The project site is a six (6) acre tract located on Market Street in Wilmington, NC.
The soils of the site consist of siltly sands with grades ranging from 0% to 1 %.
Approximately 1.26 acres will be graded to allow construction of a 10,000 SF building
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 I
scheduled to begin as soon as all permits and approvals are obtained.
EROSION CONTROL MEASURES:
The attached plans and specifications give the requirements for erosion control
measures. Silt fencing will be provided 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 Market Street 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 the City and State
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 80% impervious area lot coverage. ( V/
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.
U
MAINTENANCE PLAN
1. 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. 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.
3. 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.
4. 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
0.50 deep to provide adequate storage volume for subsequent rains. 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.
5. 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.
6. No cut or fill slopes shall exceed a side slope of 1 vertical to 3 horizontal unless
otherwise specified on the plan. All slopes shall be seeded and stabilized within
15 days.
7. The stormwater ponds will act as sediment basins 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.
8. All disturbed areas shall be seeded within 15 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 15 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 wood or 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 rip rap at minimum two feet high and three feet thick across the