SW8040808_COMPLIANCE_20040901

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
YYYYMMDD

Permit No.
SGJe d �01?07
(to be provided by DIVA)
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORA,IWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This fortis nrov be photocopied f r arse os an orrginol
DWQ Stormwater Mana_ement 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. PROJECT INFORMATION
Project Name: Seaside Storage Center
Contact Person: Mr, Drew Powell Phone Number: [phone]
For projects with multiple basins, specify which basin this worksheet applies to:
elevatiorl.s
Basin Bottom Elevation 45.00 ft. (floor of the basin)
Permanent Pool Elevation 50.00 ft. (elevation of the orifice)
Temporary Pool Elevation 51.00 ft. (elevation of the discfictrge structiu•e oilerflotiv)
cu•eas
Permanent Pool Surface Area 10,022
Drainage Area 4.27
Impervious Area 2.70
sq. ft. (►rater stufctce area ,it the orifice elevction)
ac. (oil -site curd (?ff-site drainage to the basin)
ac. (on -site crud (?ff-siic circtinage to the basin)
vohtmes
Permanent Pool Volume 28,170 cu. ft. (combined i ohilne Of inctin ba.Sin ctw(lforebay)
Temporary Pool Volume 1 1,381 cu. ft. (vohrnte detctined ciboi,e the pei-nianettt pool)
Forebay Volume 5 017 -6 4,- -n. -- cu. ft, (approximately 20% of toial ►-olwne)
Other parcuneter.y
SA/DAi
Diameter of Orifice
Design Rainfall
Design TSS Removal 2
1ror
N" iQf�S
i
GS
4.52
1.5
1.0
90
(stu face area to drainage cured ratio front DWO table)
in. (2 to 5 dcty teinpoi'ctiy pool di-aii,--cloit,ii i-ecliiii'eO
in,
% (mininnint 85% required)
Form SWU-102 Rev 3,99 Page 1 of 4

V
Footnotes:
I When using the Di0sion SAIDA tables, the correct SAIDA ratio for permanent pool sizing should be computed based upon the
actual inipen-ious % and permanent pool depth. Linear interpolation should be employed to determine the correct N•alue for non
standard table entries.
2 In the 20 coastal counties. (lie requirement fora vegetative filler may be Nraired if the xwi detention basin is designed to provide
90% TSS removal. The NCDENR BNW manual pro -ides design tables for botli 85% TSS removal and 90'%, TSS removal.
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
b. The foreba_y 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�J1� e. If required, a 30-foot vegetative filter is provided at the outlet (include non -erosive flow
calculations)
f 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.
eT�i✓� 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.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check ogre) 0 doesXdoes not incorporate a vegetated filter at the outlet.
This system (check ogre) 0 does Kdoes not incorporate pretreatment other than a forebay.
Form SWU-102 Rev 3.99 Page 2 of 4

r,
Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs within
2 to 5 days as designed.
2. Repair eroded areas immediately, re -seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to maintain
Proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e.
stockpiling near a wet detention basin or stream, etc.).
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads _�.75_ feet in the main pond, the sediment shall be removed.
When the permanent pool depth reads ,2.25 feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
Utll in the blanks)
Permanent Pool Elevation 50,00
Sediment Re' oval El. 47.00 17/%
Sediment Removal Elevation 46.25 75%
-------------- — -------
Bottom Elc �ation 4G.00 2�"�-----------------------`------------
Bottom Elevation 45.00 , 25% /
FOREBAY
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 SvVU-102 Rev 3.99 - Page 3 of 4

7, All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that 1 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: Mr. Drew Powell
Title: _ Owner
Address: 776 Seaside Road, Sunset Beach, NC 28468
Phone: [phone]
Signature
Date:
Note: The legally responsiblelparhy should not be a hoEuco«-ners associatioii unless more than 50% of the lots have been sold and a
resident of the subdk ision leas been named the president.
1, Sabrina B, Babson , a Notary Public for the State of North Carolina
a
County of Brunswick , do hereby certify that
personally appeared before me this day of �, and acknowledge the due
execution of theigyvii� wet detention basin maintenance requirements. Witness my hand and official seal,
B. adsM, "".
0
SEAL
My commission expires October 27, 2008
Form SWU-102 Rev 3.99 Page 4 of 4