SW8021026_COMPLIANCE_20030110

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SWti�Qo�,�O
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
1�o
YYYYMMDD

DETENTION POND ANALYSIS FILE NAME: G:IDATAIWPDATAIWQSIPQND1021026.WK1
PROJECT #: SW8 021026 REVIEWER: L. Lewis
PROJECT NAME: Snows Cut Landing Subdivision
DATE:
10-Jan-03
Receiving Stream:
Teifairs Creek
Class:
SC Sw
Drainage Basin:
Cape Fear
Index No.
CPF24 18-87-31.5-1
Site Area
21.42 acres
Drainage Area
6969604? square feet
Area =
16.00 acres
The rest of site is wetland (common area
IMPERVIOUS AREAS
Rational C
54 lots @3600 194400.00 square feet
Street 80840.00 square feet
Pool 3850.00 square feet
square feet
square feet
square feet
TOTAL 909(?' [30.' square feet Rational Cc= 0.12
SURFACE AREA CALCULATION
% IMPERVIOUS 40.04%
Des. Depth 7.5
TSS: 90
VOLUME CALCULATION
Rational ?*
Des. Storm
�.DO
inches
Rv=
0.41
Bottom
-3 msl
Perm. Pool
6.0. msl
Design Pool
6.6 msl
Design SA
61696 sf
Req. Volume
2383fi<'
cf
Prov. Volume
:3t?60
cf
ORIFICE CALCULATION
Avg. Head =
Flow 02, cfs
Flow Q5, cfs
No. of Orifices
Diameter, inches
Drawdown =
days
SAIDA Ratio 1.10%
Req. SA 7679 sf
Prov. 5A >::::950,4: sf
* place a "1" in the box if Rational is used
FOREBAY
Perm. Pool Volume=
389808
Req. Forebay Volume=
77961.6
Provided Volume=
78552.00
Percent=
SA @ -
Elevation=
COMMENTS
Surface Area , Volume and Orifice are within Design Guideline:
8.46
sq. in.
3.39
sq. in.
7.07
sq. in.
0.115
cfs
in x
in

• �` . �-
r
- � = � _ �",
r +.
•Y � - wy�T N�F
S4 %�
• � ay. ci
_S

Permit Number: 56u tf C21OZ6P
(to be provided by Dll'Q)
Drainage Area Number: / c.'ni
Wet Detention Basin Operation and Maintenance Agreement
1 will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP
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 � does not incorporate a vegetated filter at the outlet.
This system (check one):
❑ does Z does not incorporate pretreatment other than a £orebay.
Important maintenance procedures:
-- Inunediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until die plants become established (commonly six weeks).
— No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
— Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
— If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
— Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be vispected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County), Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element:
Potentialproblem:
How I will remediate theproblem:
The entire BMP
Trash/debris is present,
Remove the trash/debris.
The perimeter of the wet
Areas of bare soil and/or
Regrade the soil if necessary to
detention basin
erosive gullies have formed.
remove the gully, and then plant a
ground cover and water undi it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too
Maintain vegetation at a height of
long.
approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4

Permit Number: -50 0 O z1yz67
(to be provided bY DdWQ)
Drainage Area Number:
BMP element:
Potentialproblem:
How I will remediate the roblem:
The inlet device: pipe or
The pipe is clogged.
Unclog the pipe. Dispose of the
Swale
sediment off -site.
The pipe is cracked or
Replace the pipe.
otherwise damaged.
Erosion is occurring in the
Regrade the Swale if necessary to
Swale.
smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay
Sediment has accumulated to
Search for the source of the
a depth greater than the
sediment and remedy the problem if
original design depth for
possible. Remove the sediment and
sediment storage.
dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred.
Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
revert future erosion problems.
Weeds are present.
Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf
Best professional practices
Prune according to best professional
show that pruning is needed
practices
to maintain optimal plant
health.
Plants are dead, diseased or
Determine the source of the
dying.
problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary,
Weeds are present.
Remove the weeds, preferably by
hand. if pesticide is used, wipe it on
the plants rather than s ra in .
The main treatment area
Sediment has accumulated to
Search for the source of the
a depth greater than the
sediment and remedy the problem if
original design sediment
possible. Remove the sediment and
storage depth.
dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over
Consult a professional to remove
50% of the area.
and control the algal Krowth.
Cattails, phragmites or other
Remove the plants by wiping them
invasive plants cover 50% of
with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.3 Page 2 of 4

Permit Number; c. ,t j 0,7a Z »z iG
(to be provided by DIVQ)
Drainage Area Number:
BMP element:
Potentialproblem-
How I will remediate theproblem:
The embankment
Shrubs have started to grow
Remove shrubs immediately.
on the embankment.
Evidence of muskrat or
Use traps to remove muskrats and
beaver activity is present,
consult a professional to remove
beavers.
A tree has started to grow on
Consult a darn safety specialist to
the embankment.
remove the tree.
An annual inspection by an
Make all needed repairs.
appropriate professional
shows that the embankment
needs repair.
The outlet device
Clogging has occurred.
Clean out the outlet device. Dispose
of the sediment off -site.
The outlet device is damaged
Re air or replace the outlet device.
The receiving water
Erosion or other signs of
Contact the local NC Division of
damage have occurred at the
Water Quality Regional Office, or
outlet.
the 401 Oversight Unit at 919-733-
1786.
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.
Whin the permanent pool depth reads .0 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads feet in the forebay, th e sediment
shall be removed.
Sediment Removal
Bottom Elevati
BASIN DIAGRAM
(fill in the blanks)
L. Pe rnanen
Vol
-------------- Volufi Min.
me
Sediment
Storage
F"ORRBAY
Permanent Pool Elevation (0.
Pool /�
-ol Sediment Removal Elevation -- Volume
Bottom Elevation _3 - - 1-ft n.
Sediment
Storage
MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.3 Page 3 of 4

Permit Number: '56V Fo z/0z6
(to be provided by DWQ}
I acknowledge and agree by my signature below that I am responsible for the
performance of the 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.
Project name: SNOWS CUT LAw)m)(s,
BMP drainage area number:
Print name:
Title:
Address:—
Phone: —
Signature:
Date:
Note: The legally responsible party should not be a homeowners association unless more than 50a/a of
the lots have been sold and a resident of the subdivision has been named the president.
I, a Notary Public for the State of
County of , do hereby certify that
personally appeared before me this
day of I , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
Form 5W40I-Wet Detention Basin O&M-Rev.3
Page 4 of 4

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