20080989 Ver 1_More Info Received_20080723

B&F CONSULTING, INC. ?'x-P 08' ogsq
CIVIL ENGINEERING AND LAND PLANNING SERVICES
July 23, 2008
Ms. Lia Myott
NC Division of Water Quality
Express Review Program
Mail Service Center 1650
Raleigh, NC 27699-1650
RE: Stonemont
Ms. Myott::
Please find accompanying this letter two sets of revised plans, two sets of revised calculations
including the BMP data for the level spreaders below the wet detention ponds. Also, please find the
two exhibits at 11X17 size which are changed due to meeting the requirement to bury the pipes one
foot beneath the existing invert of the stream.
1) Drainage Area for each stormwater BMP is shown on sheet CD-4. I have highlighted, in color,
each of the drainage areas.
2)
a) The ponds now show a clay liner up to normal pool elevation (Sheet CD-31-1).
b) The supplement forms and construction plans have been revised to show a 2" orifice
instead of the 1" previously shown. Note that the request in the DWQ letter was for 1.5",
but based on the request ro de-water the basin as rapidly as possible, but still meet the 24
hour minimum criteria, we found a 2" orifice would work.
3)
a) We have modified the minimum length of level spreader to the required 13'.
b) We have clarified the existing contours.
c) Please find all forms for level spreaders and vegetative strips included.
4)
a) We have revised the bypass channels to show them entering the main channel at
approximately 75 degrees. In addition, we have revised the bypass channel from Pond "C"
as requested.
b) Design information for the bypass channels is included.
c) The sections are shown on the plans. The sections for the pond bypass channels are shown
on sheets CD 3E, CD 3F and CD 3G and the section for the bypass channel for the flared
end sections at the end of the cul-de-sacs is shown on sheet D4
Thank you for your consideration.
Sincerely,
ussell Briggs, P.E.
Project Engineer, B&F Consulting, Inc.
D fl
D
JUL 2 3 2008
WETLANDSAND STOR?I'AT?)? 8R4iVC M
2805 TOBERMORY LANE • RALEIGH, NORTH CAROLINA • 27606
RUSSELL BRIGGS, P.E.: PHONE: [phone] FAX: [phone] EMAIL: RBRIGGSQ)NC.RR.COM
AMBER FARRELLY, P.E.: PHONE: [phone] FAX: [phone] EMAIL: AFARRELLY(@NC RR COM
r?
u
0
0
Stonemont &x,p 02- D999
Stormwater Calculations
B&F Consulting
2805 Tobermory Lane
Raleigh NC 27606
919 618 0180
Nos T ?FY ??08
a
NO//
Wet Detention Basin Calculations, Worksheets
and
O&M Agreements
•
S
• Stonemont
Anti-flotation calculations
Outlet structures for ponds
Provide Concrete "waffle box"
Exterior dimensions 4'X 4'
Bouyant force Concrete factor of
length width height (Ibs) (Ibs) saftey
A 4 4 1.3 1298 2803 2.2
B 4 4 1.9 1897 2803 1.5
C 4 4 1.3 1298 2803 2.2
Use concrete weight as 150 Ibs/c.f.
Thus, resistant force for concrete is (150-62.4) X 2 X 4 X 4 = 2800 lbs.
•
0

•
POND A
n
U
Permit Number:

•
(to be provided by DWQ)
Drainage Area Number:
Wet Detention Basin Operation and Maintenance Agreement
I 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 ® does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately 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 the 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 inspected 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: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. 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 until 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:
(to be provided by DWQ)
Drainage Area Number: RP4 "All
LJ
•
is
BMP element: Potential problem: How I will remediate the problem:
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
prevent 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 spraying.
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 growth.
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:
(to be provided by DWQ)
`
Drainage Area Number: I. i
•
BMP element: Potential problem: How I will remediate the problem:
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 dam 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 Repair 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.
When the permanent pool depth reads 319.0 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 324.0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
r 1
L.J
0 Permanent Pool Elevation 326.0
Sediment Removal .324.0 VPe nen Pool
- - - -- - - - - - - - - - lume Sediment Removal Elevation 319.0 - - - - - - - Volume
------------------------------------- ----4_4
ottom E evatio 322.0 in.
ement Bottom Elevation 316.0 1-ft Storage Sedimer
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.3
Page 3 of 4
•
U
Permit Number:
(to he 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: Stonemont
BMP drainage area number
"Alt
Print name: ewiz Tr, md F--s
Title: M"
Address: (40 To Wft 1yI r'W CpyQT
Phon
Signz
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, S . rt, 6 y aa,4-esI _Li7_ , a Notary Public for the State of
County of CO Gc. tC •2 , do hereby certify that
CLA.-/ o?.`S L C-eS J personally appeared before me this 3
day of -) ?ti 2?e y, and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal, 7-, t7 04 AD gM'S '
01 Af?
U
U 13
?F coop'
SEAL
•
My commission expires ?- G/ zD
Form SW401-Wet Detention Basin O&M-Rev.3
Page 4 of 4
Permit No
(to be provided by DWQ)
O?0? W ATe'q
a.r,r?? vj j?? y
WDENR
• STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part Ill) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Stonemont
Contact person Russell Briaos. P.E.
Phone number
Date
Drainage area number
a I aln l u-ui tfu
f -J ul-ub
'A'
11. DESIGN INFORMATION
Site Characteristics
Drainage area 244,371.60 ftz
Impervious area 96,703.20 ff2
% impervious 39.57 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 8,349.00 ft3
Volume provided 9,800.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth

Pre-development 1-yr, 24-hr runoff in
3
Post-development 1-yr, 24-hr runoff ft
ft3
• Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth 2.89 in
Rational C, pre-development 0.25 (unitless)
Rational C, post-development 0.55 (unitless)
Rainfall intensity: 1-yr, 24-hr storm 4.90 in/hr
Pre-development 1-yr, 24-hr peak flow 6.87 ft3/sec
Post-development 1-yr, 24-hr peak flow 15.12 ft'/sec
Pre/Post 1-yr, 24-hr peak flow control -
8.25 ft3/sec
Basin Elevations
Basin bottom elevation 316.30 ft
Sediment cleanout elevation 320.00 ft
Bottom of shelf elevation 325.50 ft
Permanent pool elevation 326.00 ft
SHWT elevation 320.00 ft
Top of shelf elevation 326.50 ft
Temporary pool elevation
, 325.40
ft
•
Form SW401-Wet Detention Basin-Rev 4
Parts I. & 11 Design Summary, Page 1 of 2
Volume and Surface Area Calculations
SA/DA ratio 1.73 (unitless)
Surface area at the bottom of shelf 4,531.00 f 2
Volume at the bottom of shelf
is 15,454.00 ft3
Permanent pool, surface area required 4,227,00 f 2
Permanent pool, surface area provided 6,038.00 ftz OK
Permanent pool volume 18,128.00 fta
Average depth for SA/DA tables 3.00 ft OK
Surface area at the top of shelf 7,637.00 ffz
Volume at the top of shelf 21,547.00 ft3
Forebay volume 3,986.00 ft3
Forebay % of permanent pool volume 21.99 % OK
Temporary pool, surface area provided 8,249.00 ft2
Drawdown Calculations
Treatment volume drawdown time 4.00 days OK
Treatment volume discharge rate 0.50 ft3/s
Pre-development 1-yr, 24-hr discharge 6.87 ft3/s OK
Post-development 1-yr, 24-hr discharge 6
78 ft3/ OK
Additional Information . s
Diameter of orifice

Design TSS removal 1
85 in

Basin side slopes
3.00 %
OK
Vegetated shelf slope 10.00 OK
Vegetated shelf width

Length of flowpath to width ratio 10.00 ft OK

Length to width ratio 3.00 OK

Trash rack for overflow & orifice? 1.50 1 OK

Freeboard provided Y (Y or N) OK

Vegetated filter provided? 1.00 ft OK
• Recorded drainage easement provided? y (Y or N) OK
Capures all runoff at ultimate build-out? y (Y or N) OK
Drain mechanism for maintenance or emer
i (Y or N) OK
genc
es drain i
via oumo

Permit No.
(to be provided by DWQ)
Form SW401-Wet Detention Basin-Rev.4
Parts I. & II. Design Summary, Page 2 of 2
•
•
•
Permit No
III. REQUIRED ITEMS CHECKLIST
(to be provided by DWQ)
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Initials
A!2 A21
.4012
-
4

Pagel Plan
Sheet No.
3e-
COE 3
Plans (1" - 50' or larger) of the entire site showing:
Design at ultimate build-out,
- Off-site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
- Proposed drainage easement and public right of way (ROM,
- Overflow device, and
Boundaries of drainage easement.
2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure,with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
Basin cross-section,
- Vegetation specification for planting shelf, and
- Filter strip.
CD 3 3. Section view of the dry detention basin (1" = 20' or larger) showing:
Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
4, If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
A6 C"4 4)5. A table of elevations
areas
incremental volum
&
,
,
es
accumulated volumes for overall pond and for frebay,
to verify volume provided.
, - C 3, ?E 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
?L Gr 7. The supporting calculations.
/?- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
9. A copy of the deed restrictions (if required).
10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acce
table s
f
p
ource o
soils information.
Form SW401-Wet Detention Basin-Rev.4
Part III. Required Items Checklist, Page 1 of 1
• Basin "A"
Area of Right of way
Impervious area in street right of way
Number of lots
Typical impervious area per lot (%)
Drive, sidewalk
Footprint
Deck
Impervious area of lots:
Total drainage area
Total impervious area, lots + r/w
% impervious
Use 40 % criteria
SA/DA ratio for 3' depth
SA
Treatment volume
•
1.83 acres
1.24 acres
11.5
600 sf
3000 sf
120 sf
3720
0.98 acres
5.61 acres
2.22
40%
40%
1.73%
0.10 acres
V =3630xRox(0.05+0.9x1,)xA
where
V = Volume of runoff to be controlled (ft3)
Ro = Design storm rainfall depth (1")
A = watershed area (ac.)
V = 8349 cf
0
•
•
Pond A
Average Pond Depth = 3.0 NOTE: Excludes sediment storage
Elevation SF Area CF Volume Shelf from e.325.5 to e.326.5
329.5 11177 49405
328 9419 33958
327.5 8317 29524
326.5 7637 21547 <-shelf
326 6038 18128 <-n.pool
325.5 4531 15486 <-shelf
324 3408 9532
322 2100 4024
320 1057 867
319 676 0 <-sediment storage elevation (start avg. depth calc here)
318 305 0
316 0 0 Sed. Storage depth = 3.0 ft
Forebay Volume
Elevation SF Area
332 1610
330 950
328 476
326 140
324 0
Water Quality Volume:
This volume occurs
CF Volume
3986
1426
0
0
0
8349 CF (above normal pool)
1.12 feet above normal pool
Set weir at 1.3' above normal pool
Volume provided = 9800
0
• Basin A
Pond Routing
1-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, 1
1-year [in/hr]
• Peak Discharge, Qp
1-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 6 hour storm
1-year [inches]
Volume of Runoff, V, from 6-hour storm
1-year [inches]
1-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
1-year [minutes]
Time Interval for Routing
• 1-year [minutes]
B
3.39
2.22
5.61
0.55
5.0
4.90
15.12
98.0
61.0
75.6
3.2
2.89
v = ((p-.2S)^2)/(p+.8s)
0.92
0.43
Tp = V/(1.39*Qp)
14.9
1
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS

Riser Barrel
12 = Weir length 24 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
327.3 = Crest elev. Weir 326 = Invert elev. barrel

326.0 = Initial elev. water level
Results
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
1 6.78 327.61 15.12
0
• ROUTING AND ANALYSIS - 1-year storm
Time Inflow Storage Stage
[mins] [cfs] [cubic ft] IN
0.0 0.0 0 326.00
1.0 0.2 0 326.00
2.0 0.7 10 326.00
3.0 1.5 50 326.01
4.0 2.5 137 326.02
5.0 3.8 289 326.04
6.0 5.3 519 326.08
7.0 6.8 836 326.12
8.0 8.4 1,246 326.18
9.0 10.0 1,752 326.26
10.0 11.4 2,351 326.34
11.0 12.7 3,037 326.44
12.0 13.7 3,799 326.55
13.0 14.5 4,623 326.65
14.0 15.0 5,494 326.76
15.0 15.1 6,393 326.87
16.0 14.9 7,300 326.99
17.0 14.4 8,196 327.10
18.0 13.6 9,059 327.21
• 19.0
20.0 12.5
11.5 9,873
10,622 327.31
327.40
21.0 10.5 11,231 327.48
22.0 9.6 11,681 327.53
23.0 8.8 11,993 327.57
24.0 8.1 12,194 327.59
25.0 7.4 12,308 327.60
26.0 6.8 12,357 327.61
27.0 6.2 12,358 327.61
28.0 5.7 12,324 327.60
29.0 5.2 12,267 327.60
30.0 4.8 12,194 327.59
31.0 4.4 12,110 327.58
32.0 4.0 12,021 327.57
33.0 3.7 11,928 327.56
34.0 3.4 11,834 327.55
35.0 3.1 11,741 327.54
36.0 2.8 11,650 327.53
37.0 2.6 11,560 327.52
38.0 2.4 11,474 327.51
327.6
Outflow
[cfs]
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.3
3.0
4.4
5.5
6.2
6.6
6.8
6.8
6.7
6.4
6.2
5.9
5.6
5.3
4.9
4.6
4.3
4.0
3.8
Outlet Hydraulics
Q_orifice Q Q_riser
em.spil
0.0
0.0
0.0
0.1
0.2
0.3
0.6
0.9
1.4
1.9
2.6
3.4
4.1
4.9
5.7
6.6
7.5
8.3
9.1
9.9
10.6
11.2
11.6
11.8
12.0
12.1
12.1
12.1
12.1
12.1
12.0
11.9
11.9
11.8
11.7
11.6
11.5
11.5
11.4
6.8 < ==maximum 1-yr
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 1.3
0 3.0
0 4.4
0 5.5
0 6.2
0 6.6
0 6.8
0 6.8
0 6.7
0 6.4
0 6.2
0 5.9
0 5.6
0 5.3
0 4.9
0 4.6
0 4.3
0 4.0
0 3.8
0
Basin A
•
Pond Routing
10-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, I
10-year [in/hr]
• Peak Discharge, Qp
10-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 24 hour storm
10-year [inches]
Volume of Runoff, V, from 24-hour storm
10-year [inches]
10-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
10-year [minutes]
Time Interval for Routing
• 10-year [minutes]
3.39
2.22
5.61
0.55
5.0
9.12
28.14
B
98.0
61.0
75.6
3.2
5.05
v = ((P-.2S)"2)/(P+.8s)
2.55
1.19
Tp = V/(1.39*Qp)
22.1
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS
•
Riser Barrel
12 = Weir length 24 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
327.3 = Crest elev. Weir 326 = Invert elev. barrel

326.0 = Initial elev. water level
Results, 10-year 24 hour '
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
10 14.08 327.86 28.14
0
• ROUTING AND ANALYSIS --10-year 24-hour storm
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_orifice Q Q_riser
[mins] [cfs] [cubic ft] [ft] [cfs] em.spil
0.0 0.0 0 326.00 0.0 0.0 0 0.0
2.0 0.6 0 326.00 0.0 0.0 0 0.0
4.0 2.2 1 326.00 0.0 0.0 0 0.0
6.0 4.8 267 326.04 0.0 0.3 0 0.0
8.0 8.2 2 326.00 0.0 0.0 0 0.0
10.0 12.0 492 326.07 0.0 0.5 0 0.0
12.0 16.0 1,211 326.18 0.0 1.3 0 0.0
14.0 19.8 2,170 326.32 0.0 2.4 0 0.0
16.0 23.2 3,359 326.49 0.0 3.7 0 0.0
18.0 25.8 4,750 326.67 0.0 5.0 0 0.0
20.0 27.5 6,300 326.86 0.0 6.5 0 0.0
22.0 28.1 7,951 327.07 0.0 8.1 0 0.0
24.0 27.6 9,639 327.28 0.0 9.7 0 0.0
26.0 26.0 11,297 327.49 3.2 11.2 0 3.2
28.0 23.5 12,665 327.64 8.0 12.4 0 8.0
30.0 20.9 13,597 327.75 11.9 13.2 0 11.9
32.0 18.6 14,138 327.81 13.7 13.7 0 14.4
34.0 16.5 14,432 327.84 13.9 13.9 0 15.8
36.0 14.7 14,588 327.86 14.0 14.0 0 16.6
38.0 13.0 14,626 327.86 14.1 14.1 0 16.8
40.0 11.6 14,564 327.86 14.0 14.0 0 16.5
42.0 10.3 14,419 327.84 13.9 13.9 0 15.8
44.0 9.2 14,203 327.82 13.7 13.7 0 14.7
46.0 8.1 13,930 327.79 13.4 13.5 0 13.4
48.0 7.2 13,614 327.75 12.0 13.2 0 12.0
50.0 6.4 13,331 327.72 10.7 13.0 0 10.7
52.0 5.7 13,075 327.69 9.6 12.8 0 9.6
54.0 5.1 12,841 327.66 8.7 12.6 0 8.7
56.0 4.5 12,627 327.64 7.8 12.4 0 7.8
58.0 4.0 12,430 327.62 7.1 12.2 0 7.1
60.0 3.6 12,248 327.60 6.4 12.1 0 6.4
62.0 3.2 12,079 327.58 5.8 11.9 0 5.8
64.0 2.8 11,923 327.56 5.2 11.8 0 5.2
66.0 2.5 11,779 327.54 4.7 11.7 0 4.7
68.0 2.2 11,644 327.53 4.3 11.5 0 4.3
70.0 2.0 11,520 327.51 3.9 11.4 0 3.9
72.0 1.8 11,404 327.50 3.6 11.3 0 3.6
74.0 1.6 11,295 327.49 3.2 11.2 0 3.2
76.0 1.4 11,197 327.48 2.9 11.1 0 2.9
327.9 14.1 < maximum 10-yr 24 hour
0
• Basin A
Pond Routing
100-yr, 6 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres)
Rational C
Composite Rational C
Time of Concentration, Tc
TIC [min]
Intensities, I
100-year [in/hr]
• Peak Discharge, Qp
100-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 6 hour storm
100-year [inches]
Volume of Runoff, V, from 6-hour storm
100-year [inches]
100-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
100-year [minutes]
Time Interval for Routing
• 100-year [minutes]
B
3.39
2.22
5.61
0.55
5.0
9.12
28.14
98.0
61.0
75.6
3.2
5.39
v = ((p-.2S)"2)/(p+.8s)
2.83
1.32
Tp = V/(1.39'Qp)
24.5
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
0 BASIN PARAMETERS

Riser Barrel
12 = Weir length 24 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
327.3 = Crest elev. Weir 326 = Invert elev. barrel

326.0 = Initial elev. water level
Results, 100-year 6 hour
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
100 14.70 327.95 28.14
0
• ROUTING AND ANALYSIS --100-year 6 hour storm
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_orifice Q
[mins] [cfs] [cubic ft] [ft] [cfs] em.spil
0.0 0.0 0 326.00 0.0 0.0 0
2.0 0.5 0 326.00 0.0 0.0 0
4.0 1.8 1 326.00 0.0 0.0 0
6.0 4.0 218 326.03 0.0 0.2 0
8.0 6.8 2 326.00 0.0 0.0 0
10.0 10.0 408 326.06 0.0 0.5 0
12.0 13.6 1,010 326.15 0.0 1.1 0
14.0 17.2 1,825 326.27 0.0 2.0 0
16.0 20.5 2,855 326.42 0.0 3.2 0
18.0 23.5 4,088 326.58 0.0 4.4 0
20.0 25.8 5,497 326.76 0.0 5.7 0
22.0 27.4 7,048 326.95 0.0 7.2 0
24.0 28.1 8,692 327.16 0.0 8.8 0
26.0 27.9 10,378 327.37 0.8 10.4 0
28.0 26.8 12,005 327.57 5.5 11.8 0
30.0 24.8 13,281 327.71 10.5 12.9 0
32.0 22.4 14,141 327.81 13.7 13.7 0
34.0 20.2 14,666 327.87 14.1 14.1 0
36.0 18.1 15,029 327.91 14.4 14.4 0
38.0 16.3 15,251 327.93 14.6 14.6 0
40.0 14.7 15,353 327.95 14.7 14.7 0
• 42.0 13.2 15,351 327.95 14.7 14.7 0
44.0 11.9 15,261 327.94 14.6 14.6 0
46.0 10.7 15,096 327.92 14.5 14.5 0
48.0 9.6 14,868 327.89 14.3 14.3 0
50.0 8.6 14,587 327.86 14.0 14.0 0
52.0 7.8 14,262 327.82 13.8 13.8 0
54.0 7.0 13,902 327.78 13.3 13.5 0
56.0 6.3 13,524 327.74 11.6 13.1 0
58.0 5.7 13,208 327.70 10.2 12.9 0
60.0 5.1 12,936 327.67 9.0 12.6 0
62.0 4.6 12,698 327.65 8.1 12.4 0
64.0 4.1 12,487 327.62 7.3 12.3 0
66.0 3.7 12,298 327.60 6.6 12.1 0
68.0 3.3 12,126 327.58 5.9 11.9 0
70.0 3.0 11,969 327.56 5.4 11.8 0
72.0 2.7 11,825 327.55 4.9 11.7 0
74.0 2.4 11,692 327.53 4.5 11.6 0
76.0 2.2 11,570 327.52 4.1 11.5 0
327.9 14.7 < maximum 100-yr 6 hour
Q_riser
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.8
5.5
10.5
14.4
17.0
18.9
20.0
20.6
20.6
20.1
19.2
18.0
16.6
15.0
13.3
11.6
10.2
9.0
8.1
7.3
6.6
5.9
5.4
4.9
4.5
4.1
0
• Basin A
Pond Routing
100-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
Tc [min]
Intensities, I
100-year [in/hr]
• Peak Discharge, Qp
100-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 24 hour storm
100-year [inches]
Volume of Runoff, V, from 24-hour storm
100-year [inches]
100-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
100-year [minutes]
Time Interval for Routing
• 100-year [minutes]
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
3.39
2.22
5.61
0.55
5.0
9.12
28.14
B
98.0
61.0
75.6
3.2
7.59
v = ((p-.2S)"2)/(p+.8s)
4.75
2.22
Tp = V/(1.39*Qp)
41.2
2
• BASIN PARAMETERS
r?
Riser Barrel
12 = Weir length 24 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
327.3 =Crest elev. Weir 326 = Invert elev. barrel

326.0 = Initial elev. water level
Results, 100-yr 24 hour
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
100 17.67 328.37 28.14
0
• ROUTING AND ANALYSIS --100-year 24 hour storm
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_orifice Q
[mins] [cfs] [cubic ft] [ft] [cfs] em.spi l
0.0 0.0 0 326.00 0.0 0.0 0
2.0 0.2 0 326.00 0.0 0.0 0
4.0 0.7 1 326.00 0.0 0.0 0
6.0 1.4 79 326.01 0.0 0.1 0
8.0 2.5 2 326.00 0.0 0.0 0
10.0 3.9 154 326.02 0.0 0.2 0
12.0 5.5 388 326.06 0.0 0.4 0
14.0 7.3 718 326.11 0.0 0.8 0
16.0 9.2 1,156 326.17 0.0 1.3 0
18.0 11.3 1,710 326.25 0.0 1.9 0
20.0 13.4 2,389 326.35 0.0 2.6 0
22.0 15.6 3,195 326.47 0.0 3.5 0
24.0 17.7 4,130 326.59 0.0 4.4 0
26.0 19.7 5,191 326.72 0.0 5.5 0
28.0 21.6 6,374 326.87 0.0 6.6 0
30.0 23.3 7,670 327.03 0.0 7.8 0
32.0 24.8 9,070 327.21 0.0 9.1 0
34.0 26.1 10,559 327.40 1.2 10.5 0
36.0 27.1 12,054 327.57 5.7 11.9 0
38.0 27.7 13,336 327.72 10.7 13.0 0
• 40.0
42.0 28.1
28.1 14,356
15,210 327.83
327.93 13.8
14.6 13.8
14.6 0
0
44.0 27.8 16,022 328.02 15.2 15.2 0
46.0 27.2 16,777 328.09 15.8 15.8 0
48.0 26.3 17,462 328.16 16.3 16.3 0
50.0 25.1 18,063 328.22 16.7 16.7 0
52.0 23.7 18,568 328.27 17.0 17.0 0
54.0 22.2 18,968 328.30 17.3 17.3 0
56.0 20.8 19,265 328.33 17.4 17.4 0
58.0 19.6 19,469 328.35 17.6 17.6 0
60.0 18.4 19,589 328.37 17.6 17.6 0
62.0 17.2 19,633 328.37 17.7 17.7 0
64.0 16.2 19,608 328.37 17.7 17.7 0
66.0 15.2 19,520 328.36 17.6 17.6 0
68.0 14.3 19,376 328.34 17.5 17.5 0
70.0 13.4 19,182 328.33 17.4 17.4 0
72.0 12.6 18,943 328.30 17.2 17.2 0
74.0 11.8 18,663 328.28 17.1 17.1 0
76.0 11.1 18,349 328.24 16.8 16.8 0
328.4 17.7 < maximum 100-yr 24 hour
Q_riser
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.2
5.7
10.7
15.4
19.8
24.1
27.9
31.5
34.8
37.6
39.9
41.6
42.8
43.5
43.8
43.6
43.1
42.3
41.1
39.7
38.1
36.4
0
• Analysis of time to empty
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_barrel Q Q_riser
[hrs] [cfs] [cubic ft] [ft] [cfs] em.spil
0.0 0.0 9,800 327.30 0.134 9.8 0 0.0
1.0 0.0 9,318 327.24 0.131 9.4 0 0.0
2.0 0.0 8,847 327.18 0.128 8.9 0 0.0
3.0 0.0 8,386 327.12 0.125 8.5 0 0.0
4.0 0.0 7,936 327.07 0.122 8.1 0 0.0
5.0 0.0 7,497 327.01 0.119 7.6 0 0.0
6.0 0.0 7,069 326.96 0.116 7.2 0 0.0
7.0 0.0 6,651 326.91 0.113 6.8 0 0.0
8.0 0.0 6,243 326.85 0.110 6.4 0 0.0
9.0 0.0 5,847 326.80 0.107 6.1 0 0.0
10.0 0.0 5,461 326.76 0.104 5.7 0 0.0
11.0 0.0 5,085 326.71 0.101 5.4 0 0.0
12.0 0.0 4,721 326.66 0.098 5.0 0 0.0
13.0 0.0 4,367 326.62 0.095 4.7 0 0.0
14.0 0.0 4,023 326.58 0.092 4.3 0 0.0
15.0 0.0 3,691 326.53 0.089 4.0 0 0.0
16.0 0.0 3,369 326.49 0.086 3.7 0 0.0
17.0 0.0 3,058 326.45 0.083 3.4 0 0.0
18.0 0.0 2,760 326.40 0.079 3.0 0 0.0
• 19.0 0.0 2,474 326.36 0.076 2.7 0 0.0
20.0 0.0 2,200 326.32 0.072
21.0 0.0 1,940 326.28 0.069
0
• Soil Investigation
Pond "A"
A hand auger was used to advance a test hole approximately 30 inches in depth in two
locations of the proposed pond. The soil found appears to be a clay loam. The soil
samples were well drained.
A clay liner is specified up to normal pool. We recommend a geotechnical engineer, or
B&F Consulting be present during construction of this pond to verify the clay lining. The
presence of the nearby stream does indicate groundwater availability at a depth of the
invert of the stream.
•
r1
U
Permit Number:
(to be provided by DWQ)
Drainage Area Number: t "A j'
• Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
• - Once a year, the soil will be aerated if necessary.
Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
re air.
is
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
r 1
?J
•
•
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
(if applicable). a roximatel three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(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: Stonemont
BMP drainage area number: i-i? p itA
Print name: Curtis Jones Jr.
Title: member
Address:_ _140Towerview Court, CM, NC
Phon
Sigr-
Date:
Note:
• 1, P1.5-Ty nn f? , a Notary Public for the State of
) vVII'TA c A/01 irn- , County of do hereby certify that
(?Ut fis _Vacs , fi'r' • personally appeared before me this 9
day of ZO , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
r
My commission expires 4.6
-Z rj 7- O/ 2a
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
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.
DWQ Project No.
• DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
1. PROJECT INFORMATION
Project Name : -1-roA
Contact Person: Cad
Level Spreader ID: Dn't j
Level Spreader Length
Drainage Area
Impervious Area
Forebay Area
Maximum Filter Strip/Buffer Slope
grass
Max. Discharge from 1 "/Hr Storm
Max. Discharge to Level Spreader
Filter Strip/ Zone 2 Buffer Vegetation
the following information):
Phone Number:
ft. (perpendicular to flow)
5i ac. (on-site and off-site drainage to the level spreader)
2.Z ac. (on-site and off-site drainage to the level spreader)
/a- cu ft. (0.2% of the contributing impervious surface area)
3 a % (6% for forested, leaf littler cover, 8% for thick ground cover
0./ cfs
, fi cfs
lk g2 W0' (thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used s
to,
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
• a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
Applicants Initials
R14 0 Project Site was visited prior to designing level spreader.
W03 Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
_ Pre-Formed Scour Holes are on flat slopes only.
No structures are located in protected buffers (must meet no practical alternatives criteria).
Design Alternative (if any) and Bypass method used:
Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.
0
l
/ < 'I
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WEIR
0 T-`
PRP A S gala
H A N N wommus.m " C
\ 13,
L EL
SPREAD
A\NNEL#? .
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1 j
2
30 LON
\/E' G E\ ATEn?,
? F(
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•

0
U
1? ,? ,

• Basin A
ByPass Channel Design
10-yr, 24 hour storm
Stonemont
•
Ten year peak discharge
less flow over level spreader
Reach 1
Longitudinal slope:
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
Reach 2
Longitudinal slope:
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
14.1 cfs
13.1 cfs
1%
4.00 vert:horiz
0
0.035
1.085 feet
2.78 feet per second
0.68 Class "1" riprap ok
7%
4.00 vert:horiz
0
0.035
0.754 feet
5.76 feet per second
3.29 Class "1" riprap ok
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
is
•
".3!2008 11:34AM COMPUTED BY: rib
CT NO.:
4GEAREA: PondA DESIGN FREQUENCY: 10-year
•
HYDRAULIC RESULTS
Discharge
efx Peak Flow
Period hrs Velocity [fps) Area (sq.ft) Hydraulic
Radius ft Normal
Qe th ft
13.1 0.5 2.77 4.73 0.53 1.09
LINER RESULTS
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
[psf) Shear Stress
[psf)
Straight Rock Riprap Unvegetated 3.33 0.88 4.91 STABLE
10in
a
L- Bottom
4.0 Width = 0.00 It 4.0
•
E
HYDRAULIC RESULTS
Discharge
efs Peak Flow
Period hrx Velocity (fps) Area (sq.ft) Hydraulic
Radius(ft) Normal
De th It
13.1 0.5 5.75 2.28 0.37 0.75
LINER RESULTS
N 0.:
SIGN FREQUENCY: 10-year
Rock Riprap (n=0.035)
S = 0.0700
1 L Bottom 1
4.0 Width = 0.00 it 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetatidn Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
Ipsf) Shear Stress
Ipsf)
Straight Rock Riprap Unvegetated 3.33 3.30 1.01 STABLE
1 Din
E
ti
J
WIDE '?. ??- - --- ? / /
1 PEEP \ WEIR - 0 I -
"P A S too /
..?
'C H ANN 13' L EL
i
SPREAD
N E-L
Z, ?ljr
11
a, R
•

POND B
•
Permit Number:
(to be provided by DP)II
Drainage Area Number: " • Wet Detention Basin Operation and Maintenance Agreement

I 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.
0
This system (check one):
® does ? does not
This system (check one):
? does ® does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately 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 the 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 inspected 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: Potential problem: How I will remediate the problem:
The entire BMP Trash/debris is resent. 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 until 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 I of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: POV-A'' 5 it
C,
•
E
BMP element: Potential problem: How I will remediate the problem:
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
prevent 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 spraying.
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 growth.
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:
(to be provided by DWQ)
Drainage Area Number: Pz„, () ,L3;1
•
BMP element: Potential problem: How I will remediate the problem:
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 dam 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 Repair 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.
When the permanent pool depth reads 323.0 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 326.0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
Permanent Pool Elevation 330.0
c:
Sediment Removal V1326.0 Pe anen Pool
- - - - - - - - - - - - Volume Sediment Removal Elevation 323.0 Volume
-------------------------------------------- ------
Bottom E eva.0 -ft Min.
Sediment Bottom Elevation 320.0 1-ft r
Storage Sedimei
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.3
Page 3 of 4
Permit Number:
(to he 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: Stonemont
BMP drainage area number: "B"
Print name: l 2T5 ?Y Jt
Title:_ *,kW rL?6 rO,_ 9WA2 J ?'d LSD T
Address: I LA12 .{ d L
Phon
Sign,
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.
a Notary Public for the State of
vi?
C , County of L?41' e , do hereby certify that
?S j.' personally appeared before me this 13
day of , 2",V, and acknowledge the due execution of the
forgoing wet detention basin aintenance requirements. Witness my hand and official
seal, 7,'
....ADq"""s
/N 0
F2.
'O(! B00
SEAL
•
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.3
Page 4 of 4
Permit No.

ITEMS
(to be provided by DWQ)
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Initials

?4-
•
Page/ Plan
Sheet No.
I. Plans (1" 50' or larger) of the entire site showing:
- Design at ultimate build-out,
- Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
- Basin dimensions,
- Pretreatment system,
- High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROW),
- Overflow device, and
- Boundaries of drainage easement.
F 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
- Outlet structure with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
Basin cross-section,
Vegetation specification for planting shelf, and
Filter strip.
Cb 3 3. Section view of the dry detention basin (1" = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior t4 use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
c-F
- ` A4C,!5
CD 3
A 7. The supporting calculations.
Aifmw 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
-- r 9. A copy of the deed restrictions (if required).
AA_*4 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration
soil maps are not an acceptable source of soils information. test. County
Form SW401-Wet Detention Basin-Rev.4
Part III. Required Items Checklist, Page 1 of 1
• Basin "B"
Area of Right of way 3.5 acres
Impervious area in street right of way 2.12 acres
Number of lots 8
Typical impervious area per lot (%)
Drive, sidewalk 600 sf
Footprint 3000 sf
Deck 120 sf
3720
LJ
Impervious area of lots: 0.68 acres
Area of Rec Center 1.004 acres
Impervious area of Rec Cen ter 0.4 acres
Total drainage area 6.90 acres
Total impervious area, lots + r/w + rec center 3.20
% impervious 46%
Use 50 % criteria 50%
SA/DA ratio for 3' depth 2.06%
SA 0.14 acres
6191.62
Treatment volume
V =3630xROx(O.05+0.9xIa)xA
where
V = Volume of runoff to be controlled (ft3)
Ro = Design storm rainfall depth (I")
A = watershed area (ac.)
V = 11717 cf
•
•
•
Pond B ,
Average P ond Depth = 3.01 (excludes sediment storage)
Elevation SF Area CF Volume Shelf from e.329.5 to e.330.5
334 11239 54420
332 9153 34052
331.5 8618 29599
330.5 7592 21494
330 6007 18094 <-n.pool 20% of NP volume = 3619 cf
329.5 4536 15458 <-shelf
328 3412 9497
326 2095 3990
324 1053 842
323 631 0 <-sediment storage elevation (start avg. depth calc here)
322 309 0
320 0 0 Sed. Storage depth = 3.0 ft
Forebay Volume
Elevation SF Area CF Volume
332 1630 4565
330 967 1968
328 476 525
326 49 0
Water Quality Volume: 12044 CF (above normal pool)
This volume occurs 1.55 feet above normal pool
Set weir at 1.9' above normal pool
Volume provided = 15068
n
Basin B
Pond Routing
1-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, I
1-year [in/hr]
. Peak Discharge, Op
1-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 6 hour storm
1-year [inches]
Volume of Runoff, V, from 6-hour storm
1-year [inches]
1-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
1-year [minutes]
Time Interval for Routing
1-year [minutes]
B
3.70
3.20
6.90
0.60
5.0
4.90
20.29
98.0
61.0
78.2
2.8
2.89
V = ((p-.2S)"2)/(p+.8s)
1.06
0.61
Tp = V/(1.39*Qp)
15.7
1
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
0.30
0.98
• BASIN PARAMETERS
•
Riser Barrel
12 = Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
331.90 = Crest elev. Weir 330 = Invert elev. barrel

330.0 = Initial elev. water level
Results
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
1 8.03 332.25 20.29
L
ROUTING AND ANALYSIS - 1-year storm
Time Inflow Storage Stage
[mins] [cfs] [cubic ft] [ft]
0.0 0.0 0 330.00
1.0 0.2 0 330.00
2.0 0.8 12 330.00
3.0 1.8 60 330.01
4.0 3.1 167 330.02
5.0 4.7 352 330.05
6.0 6.5 632 330.09
7.0 8.4 1,020 330.15
8.0 10.5 1,526 330.22
9.0 12.5 2,153 330.32
10.0 14.4 2,901 330.43
11.0 16.1 3,763 330.54
12.0 17.6 4,731 330.66
13.0 18.8 5,789 330.79
14.0 19.7 6,920 330.93
15.0 20.2 8,102 331.08
16.0 20.3 9,314 331.23
17.0 19.9 10,530 331.38
18.0 19.2 11,726 331.52
19.0 18.1 12,880 331.65
20.0 16.8 13,969 331.78
21.0 15.5 14,977 331.89
22.0 14.2 15,904 332.00
23.0 13.1 16,689 332.07
24.0 12.1 17,304 332.13
25.0 11.1 17,761 332.18
26.0 10.2 18,079 332.21
27.0 9.4 18,284 332.23
28.0 8.7 18,400 332.24
29.0 8.0 18,447 332.25
30.0 7.3 18,444 332.24
31.0 6.8 18,403 332.24
32.0 6.2 18,335 332.23
33.0 5.7 18,249 332.23
34.0 5.3 18,151 332.22
35.0 4.9 18,045 332.21
36.0 4.5 17,934 332.19
37.0 4.1 17,822 332.18
38.0 3.8 17,709 332.17
332.2
Outflow
[cfs]
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.2
2.8
4.5
5.8
6.8
7.5
7.9
8.0
8.0
7.9
7.7
7.4
7.0
6.7
6.3
6.0
5.6
Outlet Hydraulics
Q_orifice Q Q_riser
em.spil
0.0
0.0
0.0
0.1
0.3
0.5
1.0
1.6
2.4
3.3
4.5
5.8
7.0
8.4
9.9
11.4
13.0
14.6
16.1
17.5
18.8
20.0
21.1
21.9
22.5
23.0
23.3
23.5
23.6
23.7
23.7
23.6
23.6
23.5
23.4
23.3
23.2
23.0
22.9
8.0 < _= maximum 2-yr
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 1.2
0 2.8
0 4.5
0 5.8
0 6.8
0 7.5
0 7.9
0 8.0
0 8.0
0 7.9
0 7.7
0 7.4
0 7.0
0 6.7
0 6.3
0 6.0
0 5.6
0
• Basin B
Pond Routing

10-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TIC [min]
Intensities, I
10-year [in/hr]
• Peak Discharge, Op
10-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 24 hour storm
100-year [inches]
Volume of Runoff, V, from 24-hour storm
10-year [inches]
10-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
10-year [minutes]
Time Interval for Routing
• 10-year [minutes]
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
3.60
3.30
6.90
0.65
5.0
9.12
40.90
B
98.0
61.0
78.7
2.7
5.05
V = ((P-.2S)"2)/(P+.8s)
2.77
1.59
Tp = V/(1.39" Qp)
20.3
2
• BASIN PARAMETERS
•
Riser Barrel
12 =Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
331.90 = Crest elev. Weir 330 = Invert elev. barrel

330.0 = Initial elev. water level
Results 10 year 24 hour storm
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
10 19.30 332.52 40.90
0
• ROUTING AND ANALYSIS --10-year 24 hour storm
Time Inflow Storage Stage Outflow
[mins] [cfs] [cubic ft] IN [cfs]
•
Outlet Hydraulics
Q_orifice Q Q_riser
em.spil
0.0 0.0 0 330.00 0.0 0.0 0 0.0
2.0 1.0 0 330.00 0.0 0.0 0 0.0
4.0 3.8 1 330.00 0.0 0.0 0 0.0
6.0 8.2 455 330.07 0.0 0.7 0 0.0
8.0 13.7 2 330.00 0.0 0.0 0 0.0
10.0 19.9 826 330.12 0.0 1.3 0 0.0
12.0 26.2 2,022 330.30 0.0 3.1 0 0.0
14.0 31.9 3,593 330.52 0.0 5.5 0 0.0
16.0 36.5 5,506 330.76 0.0 8.0 0 0.0
18.0 39.6 7,696 331.03 0.0 10.9 0 0.0
20.0 40.9 10,071 331.32 0.0 14.0 0 0.0
22.0 40.2 12,524 331.61 0.0 17.0 0 0.0
24.0 37.7 14,937 331.89 0.0 19.9 0 0.0
26.0 33.7 17,199 332.12 4.2 22.4 0 4.2
28.0 29.6 18,969 332.30 9.9 24.2 0 9.9
30.0 26.1 20,153 332.41 14.5 25.5 0 14.5
32.0 22.9 20,845 332.48 17.5 26.2 0 17.5
34.0 20.2 21,171 332.51 19.0 26.5 0 19.0
36.0 17.8 21,243 332.52 19.3 26.6 0 19.3
38.0 15.6 21,150 332.51 18.9 26.5 0 18.9
40.0 13.7 20,955 332.49 18.0 26.3 0 18.0
42.0 12.1 20,700 332.47 16.9 26.0 0 16.9
44.0 10.6 20,414 332.44 15.6 25.7 0 15.6
46.0 9.4 20,115 332.41 14.4 25.4 0 14.4
48.0 8.2 19,815 332.38 13.1 25.1 0 13.1
50.0 7.3 19,521 332.35 12.0 24.8 0 12.0
52.0 6.4 19,238 332.32 10.9 24.5 0 10.9
54.0 5.6 18,968 332.30 9.9 24.2 0 9.9
56.0 4.9 18,712 332.27 9.0 24.0 0 9.0
58.0 4.3 18,471 332.25 8.1 23.7 0 8.1
60.0 3.8 18,246 332.23 7.4 23.5 0 7.4
62.0 3.4 18,034 332.20 6.7 23.3 0 6.7
64.0 3.0 17,837 332.19 6.0 23.1 0 6.0
66.0 2.6 17,652 332.17 5.5 22.9 0 5.5
68.0 2.3 17,481 332.15 5.0 22.7 0 5.0
70.0 2.0 17,321 33213 4.5 22.5 0 4.5
72.0 1.8 17,172 332.12 4.1 22.4 0 4.1
74.0 1.6 17,033 332.11 3.7 22.2 0 3.7
76.0 1.4 16,904 332.09 3.4 22.1 0 3.4
332.5 19.3 < _= maximum 10-yr 24 hour storm
E
• Analysis of time to empty
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_barrel Q Q_riser
[hrs] [cfs] [cubic ft] [ft] [cfs] em.spil
0.0 0.0 9,800 331.29 0.034 13.6 0 0.0
6.0 0.0 9,069 331.20 0.033 12.7 0 0.0
12.0 0.0 8,362 331.11 0.032 11.7 0 0.0
18.0 0.0 7,678 331.03 0.031 10.8 0 0.0
24.0 0.0 7,018 330.95 0.029 10.0 0 0.0
30.0 0.0 6,382 330.87 0.028 9.2 0 0.0
36.0 0.0 5,770 330.79 0.027 8.4 0 0.0
42.0 0.0 5,181 330.72 0.026 7.6 0 0.0
48.0 0.0 4,617 330.65 0.025 6.9 0 0.0
54.0 0.0 4,076 330.58 0.024 6.2 0 0.0
60.0 0.0 3,558 330.52 0.023 5.5 0 0.0
66.0 0.0 3,065 330.45 0.022 4.8 0 0.0
72.0 0.0 2,599 330.38 0.020 4.0 0 0.0
78.0 0.0 2,161 330.32 0.019 3.4 0 0.0
84.0 0.0 1,752 330.26 0.018 2.7 0 0.0
90.0 0.0 1,372 330.20 0.016 2.1 0 0.0
96.0 0.0 1,021 330.15 0.015 1.6 0 0.0
102.0 0.0 698 330.10 0.014 1.1 0 0.0
108.0 0.0 405 330.06 0.012 0.6 0 0.0
• 114.0 0.0 141 330.02 0.011 0.2 0 0.0
0
• Basin B
Pond Routing
100-yr, 6 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, I
100-year [in/hr]
• Peak Discharge, Qp
100-year [cfs]
U
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 6 hour storm
100-year [inches]
Volume of Runoff, V, from 6-hour storm
100-year [inches]
100-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
100-year [minutes]
Time Interval for Routing
100-year [minutes]
3.60
3.30
6.90
0.65
5.0
9.12
40.90
B
98.0
61.0
78.7
2.7
5.39
v = ((p-.2S)"2)/(p+.8s)
3.06
1.76
Tp = V/(1.39"Qp)
22.5
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]

•
u
BASIN PARAMETERS
Riser Barrel
12 =Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
331.90 = Crest elev. Weir 330 = Invert elev. barrel

330.0 = Initial elev. water level
Results 100 yr, 6 hour
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
100 22.21 332.58 40.90
ROUTING AND ANALYSIS --100-year storm
Time Inflow Storage Stage
[mins] [cfs] [cubic ft] [ft]
0.0 0.0 0 330.00
2.0 0.8 0 330.00
4.0 3.1 1 330.00
6.0 6.8 375 330.06
8.0 11.5 2 330.00
Outlet Hydraulics
Outflow Q_orifice Q Q_riser
[cfs] em.spil
0.0 0.0 0 0.0
0.0 0.0 0 0.0
0.0 0.0 0 0.0
0.0 0.6 0 0.0
0.0 0.0 0 0.0
• 10.0
12.0 16.9
22.6 693
1,709 330.10
330.25 0.0
0.0 1.1
2.7 0
0 0.0
0.0
14.0 28.2 3,067 330.45 0.0 4.8 0 0.0
16.0 33.1 4,756 330.67 0.0 7.0 0 0.0
18.0 37.0 6,741 330.91 0.0 9.6 0 0.0
20.0 39.7 8,963 331.19 0.0 12.5 0 0.0
22.0 40.9 11,345 331.48 0.0 15.6 0 0.0
24.0 40.4 13,796 331.76 0.0 18.6 0 0.0
26.0 38.5 16,223 332.03 1.8 21.4 0 1.8
28.0 35.1 18,423 332.24 7.9 23.7 0 7.9
30.0 31.3 20,052 332.40 14.1 25.4 0 14.1
32.0 27.9 21,084 332.50 18.6 26.4 0 18.6
34.0 24.8 21,642 332.56 21.2 27.0 0 21.2
36.0 22.1 21,862 332.58 22.2 27.2 0 22.2
38.0 19.7 21,857 332.58 22.2 27.2 0 22.2
40.0 17.6 21,708 332.57 21.5 27.1 0 21.5
42.0 15.6 21,473 332.54 20.4 26.8 0 20.4
44.0 13.9 21,189 332.51 19.1 26.5 0 19.1
46.0 12.4 20,881 332.48 17.7 26.2 0 17.7
48.0 11.0 20,565 332.45 16.3 25.9 0 16.3
50.0 9.8 20,252 332.42 14.9 25.6 0 14.9
52.0 8.8 19,946 332.39 13.7 25.2 0 13.7
54.0 7.8 19,651 332.36 12.5 24.9 0 12.5
56.0 7.0 19,371 332.34 11.4 24.6 0 11.4
58.0 6.2 19,105 332.31 10.4 24.4 0 10.4
• 60.0
62.0 5.5
4.9 18,854
18,617 332.29
332.26 9.5
8.6 24.1
23.9 0
0 9.5
8.6
64.0 4.4 18,395 332.24 7.9 23.6 0 7.9
66.0 3.9 18,187 332.22 7.2 23.4 0 7.2
68.0 3.5 17,991 332.20 6.5 23.2 0 6.5
70.0 3.1 17,808 332.18 5.9 23.0 0 5.9
72.0 2.8 17,637 332.17 5.4 22.9 0 5.4
74.0 2.5 17,477 332.15 5.0 22.7 0 5.0
76.0 2.2 17,328 332.14 4.5 22.5 0 4.5
332.6 22.2 < ==maximum 100-yr 6 hour
0
• Basin B
Pond Routing
100-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TIC [min]
Intensities, I
100-year [in/hr]
Peak Discharge, Qp
100-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 24 hour storm
100-year [inches]
Volume of Runoff, V, from 24-hour storm
100-year [inches]
100-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
100-year [minutes]
Time Interval for Routing
100-year [minutes]
3.60
3.30
6.90
0.65
5.0
9.12
40.90
B
98.0
61.0
78.7
2.7
7.59
v = ((P-.2S)"2)/(P+.8s)
5.03
2.89
Tp = V/(1.39*Qp)
36.9
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS
•
Riser Barrel
12 = Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
331.90 = Crest elev. Weir 330 = Invert elev. barrel
z
width of basin
330.0 = Initial elev. water level
Results 100 year 24 hour storm
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
100 30.27 332.90 40.90
0
ROUTING AND ANALYSIS --100-year 24 hour storm
• Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_orifice Q Q_riser
[mins] [cfs] [cubic ft] [ft] [cfs] em.spil
0.0 0.0 0 330.00 0.0 0.0 0
2.0 0.3 0 330.00 0.0 0.0 0
4.0 1.2 1 330.00 0.0 0.0 0
6.0 2.6 142 330.02 0.0 0.2 0
8.0 4.6 2 330.00 0.0 0.0 0
10.0 7.0 275 330.04 0.0 0.4 0
12.0 9.8 693 330.10 0.0 1.1 0
14.0 12.9 1,278 330.19 0.0 2.0 0
16.0 16.2 2,050 330.30 0.0 3.2 0
18.0 19.6 3,021 330.44 0.0 4.7 0
20.0 23.1 4,199 330.60 0.0 6.3 0
22.0 26.5 5,585 330.77 0.0 8.1 0
24.0 29.7 7,175 330.97 0.0 10.2 0
26.0 32.7 8,958 331.19 0.0 12.5 0
28.0 35.3 10,918 331.43 0.0 15.1 0
30.0 37.4 13,034 331.67 0.0 17.6 0
32.0 39.1 15,281 331.92 0.2 20.3 0
34.0 40.3 17,619 332.16 5.4 22.8 0
36.0 40.8 19,712 332.37 12.7 25.0 0
38.0 40.8 21,399 332.53 20.0 26.7 0
• 40.0
42.0 40.2
39.0 22,647
23,495 332.66
332.74 26.1
28.8 28.0
28.8 0
0
44.0 37.3 24,109 332.80 29.4 29.4 0
46.0 35.1 24,585 332.85 29.8 29.8 0
48.0 32.8 24,904 332.88 30.1 30.1 0
50.0 30.6 25,064 332.89 30.3 30.3 0
52.0 28.5 25,082 332.90 30.3 30.3 0
54.0 26.5 24,975 332.89 30.2 30.2 0
56.0 24.7 24,757 332.86 30.0 30.0 0
58.0 23.1 24,442 332.83 29.7 29.7 0
60.0 21.5 24,044 332.79 29.3 29.3 0
62.0 20.0 23,574 332.75 28.9 28.9 0
64.0 18.7 23,043 332.70 28.1 28.4 0
66.0 17.4 22,476 332.64 25.2 27.8 0
68.0 16.2 22,007 332.59 22.9 27.4 0
70.0 15.1 21,606 332.55 21.0 27.0 0
72.0 14.1 21,253 332.52 19.3 26.6 0
74.0 13.1 20,938 332.49 17.9 26.3 0
76.0 12.2 20,650 332.46 16.7 26.0 0
332.9 30.3 < maximum 100-yr 24 hour storm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.2
5.4
12.7
20.0
26.1
30.5
33.8
36.5
38.3
39.3
39.4
38.7
37.5
35.7
33.5
30.9
28.1
25.2
22.9
21.0
19.3
17.9
16.7
0
• Analysis of time to empty
Time Inflow Storage Stage Outflow
[hrs] [cfs] [cubic ft] IN [cfs]
0.0 0.0 12,044 331.56 0.146
2.0 0.0 10,993 331.44 0.140
4.0 0.0 9,983 331.31 0.134
6.0 0.0 9,015 331.19 0.129
8.0 0.0 8,090 331.08 0.123
10.0 0.0 7,206 330.97 0.117
12.0 0.0 6,366 330.87 0.111
14.0 0.0 5,567 330.77 0.105
16.0 0.0 4,812 330.67 0.099
18.0 0.0 4,098 330.59 0.093
20.0 0.0 3,428 330.50 0.087
22.0 0.0 2,800 330.41 0.080
24.0 0.0 2,224 330.33 0.073
26.0 0.0 1,699 330.25 0.066
28.0 0.0 1,226 330.18 0.058
30.0 0.0 805 330.12 0.051
32.0 0.0 437 330.06 0.044
34.0 0.0 122 330.02 0.036
36.0
• 38.0
120.0
63.0
66.0
69.0
0
Permit Number:
(to be provided by DWQ)
Drainage Area Number:" n
• Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
• - Once a year, the soil will be aerated if necessary.
Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will rernediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
r1
U
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
r?
?J
•
•
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
(if applicable). a roximatel three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(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: Stonemont
BMP drainage area number:
Print name: Curtis Jones Jr.
Title: member
Address: 140 Towerview Court, CM NC
Phon
Signz
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, 15T Y-?'?nn f? , a Notary Public for the State of
?v! t'? PDt' i ,nt , County of kle , do hereby certify that
(?f uehs ?ncs ,.,r . personally appeared before me this 9 7W
day of r Zpo , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
My commission expiresA_6)8w,?Ir ZY 7OZV
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
• DWO Project No.
DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
1. PROJECT INFORMATION (please complete the following information):
Project Name : C
Contact Person: - Phone Number:
Level Spreader ID: P©J?D ` 13"
Level Spreader Length 13 ft.
Drainage Area ac.
Impervious Area 3,1- ac.
Forebay Area )n J-4 cu ft.
Maximum Filter Strip/Buffer Slope %
grass
(perpendicular to flow)
(on-site and off-site drainage to the level spreader)
(on-site and off-site drainage to the level spreader)
(0.2% of the contributing impervious surface area)
(6% for forested, leaf littler cover, 8% for thick ground cover
Max. Discharge from 1"/Hr Storm 611 cfs
Max. Discharge to Level Spreader cfs
Filter Strip/ Zone 2 Buffer Vegetation (thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used
ft-
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
• requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
Pre-Formed Scour Holes are on flat slopes only.
?f?/S No structures are locatefd in protected buffers (must meet no practical alternatives criteria).
Applicants Initials
Project Site was visited prior to designing level spreader.
7
Design Alternative (if any) and Bypass method used:
l? Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
,06 Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
1210 No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.
0
•

4
•
•
L- L- V L-L-
4.0
• Basin B
ByPass Channel Design
10-yr, 24 hour storm
Stonemont
n
U
Ten year peak discharge
less flow over level spreader
Reach 1
Longitudinal slope:
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
Reach 2
Longitudinal slope:
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
19.3 cfs
18.3 cfs
17%
4.00 vert:horiz
7
0.035
0.725 feet
8.70 feet per second
7.69 Class "1" riprap ok
5%
4.00 vert:horiz
0
0.030
0.86 feet
6.19 feet per second
2.68 Class "1" riprap ok
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]

•
HYDRAULIC RESULTS
Discharge
cfs Peak Flow
Period hrs Velocity [fps) Area (sq.ft) Hydraulic
Radius ft Normal
De th ft
08.3 0.5 7.23 2.53 0.27 0.31
Pond B
Rock Riprap
S = 0.1700
1 L 1
Bottom
4.0 Width = 7.00 ft 4.0
LINER RESULTS
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psf) Shear Stress
(psf)
Straight Rock Riprap Unvegetated 3.33 3.26 1.02 STABLE
1 Din
Back to Input Screen [
0
is Soil Investigation
Pond "B"
A hand auger was used to advance a test hole approximately 30 inches in depth in two
locations of the proposed pond. The soil found appears to be a sandy loam, with a
predominance of quartz material throughout the sample. The soil samples were well
drained.
A clay liner is specified up to normal pool. We recommend a geotechnical engineer, or
B&F Consulting be present during construction of this pond to verify the clay lining. The
presence of the nearby stream does indicate groundwater availability at a depth of the
invert of the stream.
0

Permit Number:
•
•
(to be provided by DWQ)
Drainage Area Number: . '' it
Wet Detention Basin Operation and Maintenance Agreement
I 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 ® does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately 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 the 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.
r1
LJ
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected 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: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. 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 until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long, a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.3
Page 1 of 4
Permit Number:
(to be .,provided by DWQ)
Drainage Area Number: ' 'C_
•
•

BMP element: Potential problem: How I will remediate the problem:
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
prevent 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 spraying.
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 growth.
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:
(to be provided by DWQ)
Drainage Area Number:
11
BMP element: Potential problem: How I will remediate the problem:
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 dam 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 Repair 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.
When the permanent pool depth reads 316.0 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 320.0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
•
V Permanent Pool Elevation 324.0
Sediment Removal E. 320.0 rPeanen Pool
- - - - - - - - - - - lume Sediment Removal Elevation 316.0 Volume
-------------------------------------------- 41,
Bottom E evatio 318.0 in.
Seiment Bottom Elevation 313.6 1-ft Storage Sedimet
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.3
Page 3 of 4
Permit Number:
(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: Stonemont
BMP drainage area number: "C"
Print name: 6rlzs ?_?M J-/-.
?yLsti„B,r.?
Address: /* &' .0CV/eW C/% LA-e-e ,(/c
Phon
Sign,
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, S• Z? 6 y -S' , a Notary Public for the State of
• in.2 C , County of (,064- , do hereby certify that
(fL'_"A S L Tie _S -j-v- personally appeared before me this J
day of J ?.y , ZCO ? , and acknowledge the due execution of the
forgoing wet detention basin ai enance requirements. Witness my hand and official
seal,
vo.
17- v
,o ECG
UB'
SEAL
My commission expires ? -y ul/
•
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4
Permit No.
(to be provided by DWQ)
Jill. REQUIRED ITEMS CHECKLIST
• Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Initials
Pagel Plan
Sheet No.
r 1
Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
- Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
- Basin dimensions,
- Pretreatment system,
- High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROM,
- Overflow device, and
- Boundaries of drainage easement.
1)0 CP_?3j
Ll

2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
- Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
Basin cross-section,
Vegetation specification for planting shelf, and
- Filter strip.
3. Section view of the dry detention basin (1" = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
GD 3 3U 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
11
k* 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,

CD?3 36 to verify volume provided.
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
r 'F? -?"?Ag 7. The supporting calculations.
-Aff*CW 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
'x_ 9. A copy of the deed restrictions (if required).
10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
•
Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1
• Basin "C"
Area of Right of way 1.72 acres
Impervious area in street right of way 1.28 acres
Number of lots 17
Typical impervious area per lot (%)
Drive, sidewalk 600 sf
Footprint 3000 sf
Deck 120 sf
3720
•
Impervious area of lots: 1.45 acres
Total drainage area 6.90 acres
Total impervious area, lots + r/w 2.73
% impervious 40%
Use 40% criteria 40%
SA/DA ratio for 3' depth 1.73%
SA 0.12 acres
Treatment volume
V =3630xRox(0.05+0.9x1a)xA
where
V = Volume of runoff to be controlled (ft3)
Ro = Design storm rainfall depth (I")
A = watershed area (ac.)
Treatment volume = 10177 cubic feet

•
•
Pond C
Average Pond Depth = 3.03 (excludes sediment storage)
Elevation SF Area CF Volume Shelf from e.323.5 to e.324.5
327.5 12349 55827
326 10431 38742
325.3 9595.2 32067 water quality pool
324.5 8640 24438 <-shelf (upper)
324 6800 20578 <-n.pool 20% of NP volume = 4116 cf
323.5 5155 17590 <-shelf (lower) 1543 sf
322 3751 10910
320 2242 4917
318 1143 1532
316 389 0 <-sediment storage elevation (start avg. depth calc here)
315 159 0
314 20 0
313.6 0 0 Sed. Storage depth = 2.4 ft
Forebay Volume
Elevation SF Area CF Volume
326 1644 4953
324 996 2313
322 475 842
320 176 191
318 15 0
Water Quality Volume: 10177 CF (above normal pool)
This volume occurs 1.16 feet above normal pool
Set weir at 1.3' above normal pool
Volume provided = 11488 cubic feet
0
• Pond "C"
Pond Rou
ting
1-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, I
1-year [i n/h r]
0 Peak Discharge, Qp
1-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 6 hour storm
1-year [inches]
Volume of Runoff, V, from 6-hour storm
1-year [inches]
1-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
1-year [minutes]
Time Interval for Routing
• 1-year [minutes]
4.17
2.73
6.90
0.55
5.0
4.90
18.60
B
98.0
61.0
75.6
3.2
2.89
v = ((p-.2S)"2)/(p+.8s)
0.92
0.53
Tp = V/(1.39" Qp)
14.9
1
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS
•
Riser Barrel
12 = Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
325.30 = Crest elev. Weir 324 = Invert elev. barrel

324.0 = Initial elev. water level
Results
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
1 8.68 ' 325.66 18.60
0
• ROUTING AND ANALYSIS - 1-year storm
Time Inflow Storage Stage
[mins] [cfs] [cubic ft] [ft]
0.0 0.0 0 324.00
1.0 0.2 0 324.00
2.0 0.8 12 324.00
3.0 1.8 61 324.01
4.0 3.1 169 324.02
5.0 4.7 356 324.05
6.0 6.5 638 324.08
7.0 8.4 1,028 324.13
8.0 10.4 1,533 324.20
9.0 12.3 2,155 324.28
10.0 14.1 2,892 324.37
11.0 15.6 3,736 324.48
12.0 16.9 4,673 324.59
13.0 17.9 5,688 324.70
14.0 18.4 6,759 324.82
15.0 18.6 7,865 324.94
16.0 18.3 8,980 325.06
17.0 17.7 10,081 325.18
18.0 16.7 11,143 325.30
19.0 15.4 12,144 325.40
20.0 14.1 12,993 325.48
21.0 12.9 13,652 325.55
22.0 11.8 14,131 325.60
23.0 10.9 14,456 325.63
24.0 9.9 14,657 325.65
25.0 9.1 14,762 325.66
26.0 8.4 14,795 325.66
27.0 7.7 14,775 325.66
28.0 7.0 14,718 325.66
29.0 6.4 14,634 325.65
30.0 5.9 14,533 325.64
31.0 5.4 14,421 325.63
32.0 4.9 14,302 325.61
33.0 4.5 14,180 325.60
34.0 4.2 14,058 325.59
35.0 3.8 13,936 325.58
36.0 3.5 13,817 325.57
37.0 3.2 13,700 325.55
38.0 2.9 13,588 325.54
325.7
Outflow
[cfs]
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.2
3.1
4.9
6.4
7.5
8.2
8.6
8.7
8.6
8.4
8.1
7.8
7.4
7.0
6.6
6.2
5.8
5.4
5.1
4.7
Outlet Hydraulics
Q_orifice Q Q_riser
em.spil
0.0
0.0
0.0
0.1
0.2
0.5
0.9
1.4
2.1
2.9
4.0
5.1
6.2
7.4
8.6
9.9
11.2
12.5
13.7
14.8
15.7
16.4
16.9
17.2
17.4
17.5
17.6
17.5
17.5
17.4
17.3
17.2
17.0
16.9
16.8
16.7
16.5
16.4
16.3
8.7 < ==maximum 2-yr
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 0.0
0 1.2
0 3.1
0 4.9
0 6.4
0 7.5
0 8.2
0 8.6
0 8.7
0 8.6
0 8.4
0 8.1
0 7.8
0 7.4
0 7.0
0 6.6
0 6.2
0 5.8
0 5.4
0 5.1
0 4.7
0
• Pond "C"
Pond Rou
ting
10-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TIC [min]
Intensities, I
10-year [in/hr]
is Peak Discharge, Qp
10-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 24 hour storm
10-year [inches]
Volume of Runoff, V, from 6-hour storm
10-year [inches]
10-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
10-year [minutes]
Time Interval for Routing
• 10-year [minutes]
4.17
2.73
6.90
0.55
5.0
7.24
27.48
B
98.0
61.0
75.6
3.2
5.05
v = ((p-.2S)"2)/(p+.8s)
2.55
1.46
Tp = V/(1.39"Qp)
27.8
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS
0
Riser Barrel
12 = Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
325.15 = Crest elev. Weir 324 = Invert elev. barrel

324.0 = Initial elev. water level
Results 10-year 24-hour storm
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
10 22.95 326.17 27.48

• ROUTING AND ANALYSIS --10-year, 24 hour storm
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_orifice Q Q_riser
[mins] [cfs] [cubic ft] IN [cfs] em.spil
0.0 0.0 0 324.00 0.0 0.0 0 0.0
2.0 0.3 0 324.00 0.0 0.0 0 0.0
4.0 1.4 42 324.01 0.0 0.1 0 0.0
6.0 3.0 207 324.03 0.0 0.3 0 0.0
8.0 5.2 571 324.07 0.0 0.8 0 0.0
10.0 7.9 1,199 324.16 0.0 1.6 0 0.0
12.0 10.8 2,143 324.28 0.0 2.9 0 0.0
14.0 13.9 3,439 324.45 0.0 4.7 0 0.0
16.0 16.9 5,104 324.64 0.0 6.7 0 0.0
18.0 19.9 7,138 324.86 0.0 9.1 0 0.0
20.0 22.5 9,521 325.12 0.0 11.8 0 0.0
22.0 24.6 12,216 325.41 1.4 14.8 0 1.4
24.0 26.2 15,006 325.68 9.4 17.8 0 9.4
26.0 27.2 17,018 325.89 17.7 19.9 0 17.7
28.0 27.5 18,151 326.00 21.1 21.1 0 23.1
30.0 27.1 18,916 326.07 21.8 21.8 0 26.6
32.0 26.0 19,547 326.12 22.4 22.4 0 29.5
34.0 24.3 19,977 326.16 22.8 22.8 0 31.5
36.0 22.2 20,155 326.17 23.0 23.0 0 32.4
38.0 20.2 20,062 326.17 22.9 22.9 0 32.0
40.0 18.4 19,741 326.14 22.6 22.6 0 30.4
• 42.0 16.8 19,240 326.09 22.1 22.1 0 28.0
44.0 15.3 18,598 326.04 21.5 21.5 0 25.1
46.0 13.9 17,848 325.97 20.8 20.8 0 21.6
48.0 12.7 17,023 325.89 17.8 19.9 0 17.8
50.0 11.5 16,410 325.82 15.1 19.3 0 15.1
52.0 10.5 15,986 325.78 13.3 18.8 0 13.3
54.0 9.6 15,653 325.75 11.9 18.5 0 11.9
56.0 8.7 15,369 325.72 10.8 18.2 0 10.8
58.0 7.9 15,117 325.70 9.9 17.9 0 9.9
60.0 7.2 14,885 325.67 9.0 17.7 0 9.0
62.0 6.6 14,671 325.65 8.2 17.4 0 8.2
64.0 6.0 14,472 325.63 7.6 17.2 0 7.6
66.0 5.5 14,285 325.61 6.9 17.0 0 6.9
68.0 5.0 14,109 325.60 6.3 16.8 0 6.3
70.0 4.5 13,944 325.58 5.8 16.7 0 5.8
72.0 4.1 13,788 325.56 5.3 16.5 0 5.3
74.0 3.8 13,642 325.55 4.9 16.3 0 4.9
76.0 3.4 13,504 325.53 4.5 16.2 0 4.5
326.2 23.0 < maximum 10-yr 24 hr storm
0
• Pond "C"
Pond Rou
ting
100-yr, 6 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, I
100-year [in/hr]
is Peak Discharge, Qp
100-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 6 hour storm
100-year [inches]
Volume of Runoff, V, from 6-hour storm
100-year [inches]
100-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
100-year [minutes]
Time Interval for Routing
• 100-year [minutes]
4.17
2.73
6.90
0.55
5.0
9.12
34.61
B
98.0
61.0
75.6
3.2
5.39
v = ((p-.2S)"2)/(p+.8s)
2.83
1.63
Tp = V/(1.39"Qp)
24.5
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS
•
Riser Barrel
12 =Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
325.15 = Crest elev. Weir 324 = Invert elev. barrel

324.0 = Initial elev. water level
Results 100-year 6 hour
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
100 26.23 326.49 34.61
0
ROUTING AND ANALYSIS --100-year, 6 hour storm
Outlet Hydraulics
Time Inflow Storage Stage .Outflow Q_orifice Q Q_riser
[mins] [cfs] [cubic ft] IN [cfs] em.spil
0.0 0.0 0 324.00 0.0 0.0 0 0.0
2.0 0.6 0 324.00 0.0 0.0 0 0.0
4.0 2.2 68 324.01 0.0 0.1 0 0.0
6.0 4.9 334 324.04 0.0 0.5 0 0.0
8.0 8.3 918 324.12 0.0 1.3 0 0.0
10.0 12.4 1,915 324.25 0.0 2.6 0 0.0
12.0 16.7 3,398 324.44 0.0 4.6 0 0.0
14.0 21.1 5,404 324.67 0.0 7.1 0 0.0
16.0 25.3 7,937 324.95 0.0 10.0 0 0.0
18.0 28.9 10,970 325.28 0.0 13.5 0 0.0
20.0 31.8 14,438 325.63 7.4 17.2 0 7.4
22.0 33.7 17,358 325.92 19.3 20.3 0 19.3
24.0 34.6 19,086 326.08 22.0 22.0 0 27.3
26.0 34.3 20,599 326.21 23.4 23.4 0 34.6
28.0 32.9 21,912 326.33 24.6 24.6 0 41.3
30.0 30.5 22,914 326.42 25.5 25.5 0 46.8
32.0 27.6 23,518 326.47 26.1 26.1 0 50.1
34.0 24.8 23,697 326.49 26.2 26.2 0 51.1
36.0 22.3 23,523 326.47 26.1 26.1 0 50.2
38.0 20.1 23,070 326.43 25.7 25.7 0 47.6
40.0 18.0 22,398 326.37 25.0 25.0 0 43.9
42.0 16.2 21,559 326.30 24.3 24.3 0 39.5
44.0 14.6 20,595 326.21 23.4 23.4 0 34.6
46.0 13.1 19,543 326.12 22.4 22.4 0 29.5
48.0 11.8 18,431 326.02 21.4 21.4 0 24.4
50.0 10.6 17,285 325.91 19.0 20.2 0 19.0
52.0 9.5 16,282 325.81 14.5 19.1 0 14.5
54.0 8.6 15,687 325.75 12.1 18.5 0 12.1
56.0 7.7 15,270 325.71 10.4 18.1 0 10.4
58.0 6.9 14,945 325.68 9.2 17.7 0 9.2
60.0 6.3 14,672 325.65 8.2 17.4 0 8.2
62.0 5.6 14,432 325.63 7.4 17.2 0 7.4
64.0 5.1 14,217 325.61 6.7 16.9 0 6.7
66.0 4.5 14,020 325.59 6.1 16.7 0 6.1
68.0 4.1 13,838 325.57 5.5 16.5 0 5.5
70.0 3.7 13,669 325.55 5.0 16.4 0 5.0
72.0 3.3 13,512 325.54 4.5 16.2 0 4.5
74.0 3.0 13,366 325.52 4.1 16.1 0 4.1
76.0 2.7 13,230 325.51 3.7 15.9 0 3.7
326.5 26.2 < ==maximum 100-yr 6 hour
•
• Pond "C"
Pond Routing
100-yr, 24 hour storm
Stonemont
HYDROGRAPH PARAMETERS
Item
Drainage Area
Area Type
Lawn, Landscape [acres]
Impervious [acres]
Drainage Area [acres]
Rational C
Composite Rational C
Time of Concentration, Tc
TC [min]
Intensities, I
100-year [in/hr]
• Peak Discharge, Qp
100-year [cfs]
Curve Number, CN
Hydrologic Soil Group
Impervious CN
Lawn, Landscaped CN
Composite CN
S
Precipitation Amount, P for 24 hour storm
100-year [inches]
Volume of Runoff, V, from 24-hour storm
100-year [inches]
100-year [acre-feet]
Time-to-Peak, Tp (for use in routing)
100-year [minutes]
Time Interval for Routing
• 100-year [minutes]
4.17
2.73
6.90
0.55
5.0
9.12
34.61
B
98.0
61.0
75.6
3.2
7.59
v = ((p-.2S)"2)/(p+.8s)
4.75
2.73
Tp = V/(1.39*Qp)
41.2
2
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
• BASIN PARAMETERS
c:
Riser Barrel
12 = Weir length 30 = Dia. barrel (inches)
3.3 = Cw weir 0.6 = Cd barrel
325.15 = Crest elev. Weir 324 = Invert elev. barrel

324.0 = Initial elev. water level
Results 100-year, 24-hour storm
Event Post Development
With Controls No Control
Peak Peak Peak
Discharge Elevation Discharge
[cfs] [cfs]
100 29.28 326.79 34.61
0
• ROUTING AND ANALYSIS --100-year, 24 hour storm
Outlet Hydraulics
Time Inflow Storage Stage Outflow Q_orifice Q
[mins] [cfs] [cubic ft] [ft] [cfs] em.spil
0.0 0.0 0 324.00 0.0 0.0 0
2.0 0.2 0 324.00 0.0 0.0 0
4.0 0.8 24 324.00 0.0 0.0 0
6.0 1.8 120 324.02 0.0 0.2 0
8.0 3.1 334 324.04 0.0 0.5 0
10.0 4.8 709 324.09 0.0 1.0 0
12.0 6.8 1,284 324.17 0.0 1.8 0
14.0 9.0 2,096 324.27 0.0 2.9 0
16.0 11.4 3,172 324.41 0.0 4.3 0
18.0 13.9 4,536 324.57 0.0 6.1 0
20.0 16.5 6,205 324.76 0.0 8.0 0
22.0 19.2 8,189 324.97 0.0 10.3 0
24.0 21.8 10,488 325.23 0.0 12.9 0
26.0 24.2 13,099 325.49 3.4 15.8 0
28.0 26.6 15,602 325.74 11.7 18.4 0
30.0 28.7 17,384 325.92 19.4 20.3 0
32.0 30.5 18,495 326.03 21.4 21.4 0
34.0 32.1 19,590 326.13 22.4 22.4 0
36.0 33.3 20,748 326.23 23.5 23.5 0
38.0 34.1 21,921 326.33 24.6 24.6 0
40.0 34.5 23,063 326.43 25.6 25.6 0
42.0 34.6 24,130 326.52 26.6 26.6 0
44.0 34.2 25,083 326.61 27.5 27.5 0
46.0 33.5 25,889 326.68 28.2 28.2 0
48.0 32.3 26,519 326.73 28.7 28.7 0
50.0 30.8 26,948 326.77 29.1 29.1 0
52.0 29.1 27,156 326.79 29.3 29.3 0
54.0 27.3 27,133 326.79 29.3 29.3 0
56.0 25.6 26,899 326.77 29.1 29.1 0
58.0 24.1 26,488 326.73 28.7 28.7 0
60.0 22.6 25,930 326.68 28.2 28.2 0
62.0 21.2 25,253 326.62 27.6 27.6 0
64.0 19.9 24,481 326.55 27.0 27.0 0
66.0 18.7 23,637 326.48 26.2 26.2 0
68.0 17.6 22,739 326.40 25.3 25.3 0
70.0 16.5 21,804 326.32 24.5 24.5 0
72.0 15.5 20,844 326.24 23.6 23.6 0
74.0 14.5 19,869 326.15 22.7 22.7 0
76.0 13.6 18,890 326.06 21.8 21.8 0
326.8 29.3 < _= maximum 100-yr 24-hr storm
Q_riser
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.4
11.7
19.4
24.7
29.7
35.3
41.4
47.6
53.6
59.2
64.1
68.0
70.7
72.0
71.8
70.4
67.8
64.3
60.2
55.7
50.8
45.8
40.8
35.8
31.0
26.4
is
Analysis of time to empty
Time Inflow Storage Stage Outflow
[hrs] [cfs] [cubic ft] [ft] [cfs]
0.0 0.0 11,154 325.30 0.134
2.0 0.0 10,190 325.19 0.129
4.0 0.0 9,264 325.09 0.123
6.0 0.0 8,376 325.00 0.118
8.0 0.0 7,525 324.90 0.113
10.0 0.0 6,711 324.81 0.108
12.0 0.0 5,936 324.73 0.102
14.0 0.0 5,198 324.65 0.097
16.0 0.0 4,498 324.57 0.092
18.0 0.0 3,835 324.50 0.087
20.0 0.0 3,211 324.42 0.080
22.0 0.0 2,632 324.34 0.074
24.0 0.0 2,099 324.27 0.068
26.0 0.0 1,610 324.21 0.061
28.0 0.0 1,168 324.15 0.055
30.0 0.0 771 324.10 0.049
32.0 0.0 420 324.05 0.042
34.0 0.0 116 324.02 0.036
•
66.0
69.0
0
Permit Number:
(to be provided by DWQ)
Drainage Area Number: -' "
• Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
• - Once a year, the soil will be aerated if necessary.
Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/ debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
•
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3

•
•
BMP element: Potential problem: How I will remediate the problem:
The Swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
(if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(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: Stonemont
BMP drainage area number: P d i
Print name: Curtis Jones, Jr.
Title: member
Address: 140 Towerview Court, CM, NQ
Phon
Sigm
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, 15?Y L •nn ?? , a Notary Public for the State of
A014 atOI /? County of kikl , do hereby certify that
(fu .Mmes '_'/r • personally appeared before me this 9 -rd
day of ? Zbv , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
My commission expires_4F,8 Z tT 7 p/
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Witness my hand and official seal,
• DWQ Project No..
DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
the following information):
Phone Number:
Level Spreader ID: (1>
1. PROJECT INFORMATION (please
Project Name :
Contact Person: Rol
Level Spreader Length 13 ft.
Drainage Area ac.
Impervious Area ac.
Forebay Area cu ft.
Maximum Filter Strip/Buffer Slope 7` a %
grass
Max. Discharge from 1"/Hr Storm y, 1 cfs
(perpendicular to flow)
(on-site and off-site drainage to the level spreader)
(on-site and off-site drainage to the level spreader)
(0.2% of the contributing impervious surface area)
(6% for forested, leaf littler cover, 8% for thick ground cover
Max. Discharge to Level Spreader i' 0 cfs
Filter Strip/ Zone 2 Buffer Vegetation ??? (thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. /f a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
• a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
roject Site was visited prior to designing level spreader.
Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
A_Pre-Formed Scour Holes are on flat slopes only.
No structures are located in protected buffers (must meet no practical alternatives criteria).
Applicants Initials
P
Design Alternative (if any) and Bypass method used:
Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.
0
CJ

•
0
E ? '?

t
1
i
t

9

13' EVEL
SP FADER
WE /R N
R
L
327.

f`
I
I
• Basin C
Bypass Channel Design
10-yr, 24 hour storm
Stonemont
Ten year peak discharge
less flow over level spreader
Reach 1
Longitudinal slope:
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
•
23 cfs
22 cfs
5%
4.00 vert: horiz
0
0.035
0.98 feet
5.73 feet per second
3.06 Class "1" riprap ok
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
f?J
zzto

D
I

I rA rl- i
L/ON 11
DER,,.
R
13' EVEL
SP EADERl -_

t

z
" /j
I

•
C
Green - ECMDS Version
HYDRAULIC RESULTS
STATION/REACH:
Discharge
cfs Peak Flow
Period hrs Velocity [fps) Area (sq.ft) Hydraulic
Radius fk Normal
De th ft
22.0 0.5 5.77 3.81 0.47 0.98
LINER RESULTS
Pond C DESIGN FREQUENCY:
Rock Riprap [n=0.0351
S = 0.0500
1 L Bottom 1
4.0 Width = 0.00 It 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psf) Shear Stress
(psf)
Straight Rock Riprap Unvegetated 3.33 3.05 1.09 STABLE
1 Din
/23!2008
0
Soil Investigation
Pond "C"
A hand auger was used to advance a test hole approximately 30 inches in depth in two
locations of the proposed pond. The soil found appears to be a sandy loam, with a
predominance of quartz material throughout the sample. The soil samples were well
drained.
A clay liner is specified up to normal pool. We recommend a geotechnical engineer, or
B&F Consulting be present during construction of this pond to verify the clay lining. The
presence of the nearby stream does indicate groundwater availability at a depth of the
invert of the stream.
•
Ah
•

•
Permit Number:
(to be provided by DWQ)
Drainage Area Number: ri_
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the'filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will, be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element:
The entire filter strip
Potential problem:
Trash/ debris is present.
How I will remediate the
Remove the trash/debris.
The flow splitter device
(if applicable)
The flow splitter device is
The flow splitter device is
damaged.
Unclog the conveyance and dispose
of any sediment off-site.
Make any necessary repairs or
replace if damage is too large for
Form SWU401 -Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
•
•
•
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
' reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(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: Stonemont
BMP drainage area number:-
Print name: Curtis Jones Jr. ,
Title: member
Address: 140 Towerview Court, Cga, NC
Phone:
Signatu e:
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, 15?Y L- k", Ae-JI , a Notary Public for the State of
4101 yn P 1 AD , County of
Wke , do hereby certify that
CUt personally appeared before me this 9 ?;
day of .?' 2008, and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
My commission expires k1a) 7- ? of D
Form SWU401-Level Spreader, Filter Sirip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Witness my hand and official seal,
DWQ Project No.
• DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
1. PROJECT INFORMATION (please complete the following information):
Project Name
Contact Person:
Level Spreader ID:
Level Spreader Length
Drainage Area
Impervious Area
Forebay Area
Maximum Filter Strip/Buffer Slope
grass
Max. Discharge from 1"/Hr Storm
Max. Discharge to Level Spreader
Filter Strip/ Zone 2 Buffer Vegetation
13 ft.
e :_3I ac.
ac.
cu ft.
. 3 cfs
© cfs
Pre-treatment or Bypass Method Used
II. REQUIRED ITEMS CHECKLIST
(perpendicular to flow)
(on-site and off-site drainage to the level spreader)
(on-site and off-site drainage to the level spreader)
(0.2% of the contributing impervious surface area)
(6% for forested, leaf littler cover, 8% for thick ground cover
(thick ground cover or grass; canopied forest with leaf litter
groundcover)
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
• a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
Applicants Initials
Project Site was visited prior to designing level spreader.
1"e rDate of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
;no Q Pre-Formed Scour Holes are on flat slopes only.
Rffi No structures are located in protected buffers (must meet no practical alternatives criteria).
Design Alternative (if any) and Bypass method used:
Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
JeA6 Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.

•
d-

?.?
44
9
• FES 4
Bypass Channel Design
10-yr, 24 hour storm
Stonemont
•
Drainage Area
Intenstiy
Rational C
Impervious area
Forebay Area
Flow to level spreader
length of level spreader
Set min. length as 13'
Set flow through level spreader as
Estimate of Q10
Intensity
Q10
Flow through by-pass channel
Reach 1
Longitudim
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
0.31 acres
1 inch/hour
0.85
0.25 acres
22 cu.ft.
0.3 cfs
3.4 feet
1.0 cfs
7.22
1.9 cfs
0.9
5%
4.00 vert:horiz
0
0.035
0.3 feet
2.5 feet per second
0.94 Grass ok; provide lining for establishment
0
•
E
HYDRAULIC RESULTS
STA
Discharge
cfx Peak Flow
Period hrs Velocity (fps) Area (sq.ft) Hydraulic
Radius ft Normal
De th ft
0.9 0.5 2.59
1 0
0.14
0.29
LINER RESULTS
Unreinforced
SIGN FREQUENCY: 10-year
Sam/
1 L Bottom ?J 1
4.0 Width = 0.00 ft 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psf) Shear Stress
(psf)
Straight Unreinforced Vegetation D Mis 75.95% 3.33 0.92 3.63 STABLE
Soil Sandy Loam 0.035 0.046 0.77 UNSTABLE
0
•
•
HYDRAULIC RESULTS
I Discharge
cfs Peak Flow
Period his Velocity (fps] Area [sq.ft] Hydraulic
Radius ft Nd}mal
Depth ft
0.9 0.5 1.85 0.49 0.17 0.35
LINER RESULTS
AREA: FES 4
S75 (n=0.055)
S = 0.0500
1 L Bottom 1
4.0 Width = 0.00 It 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(PSI) Shear Stress
(Psf)
Straight S75 Unvegetated 1.55 1.09 1.42 STABLE
Staple D
Back to Input Screen
0
Permit Number:
(to be provided_ QW
Drainage Area Number:
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
• - Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/ debris is present. Remove the trash/debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
re air.

Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page I of 3

BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo a of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if a licable . approximately three to six inches.
0 Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
r?
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
is 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: Stonemont
BMP drainage area number:
Print name: Curtis Jones Jr.
Title: member
Address: 140 Towerview Court Cary, NC
Phone:
SignE
Oate:
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' PI-5-ry L. a Notary Public rD Iy for the State of
?IV/ -A1 D__ (/ran County of W k , do hereby certify that
personally appeared before me this 9 7W
day of Z6O , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
My commission expires k "'. ' 2T_ 7-O/?1
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
DWQ Project No
• DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
1. PROJECT INFORMATION (please complete the following information):
Project Name
Contact Person: I &C'.. PC Phonf
Level Spreader ID:
Level Spreader Length 13 ft. (perpendicular to flow)
Drainage Area 0, 44 - ac. (on-site and off-site drainage to the level spreader)
Impervious Area Da 15 ac. (on-site and off-site drainage to the level spreader)
Forebay Area /cu ft. (0.2% of the contributing impervious surface area)
Maximum Filter Strip/Buffer Slope '07 % (6% for forested, leaf littler cover, 8% for thick ground cover
grass
Max. Discharge from 1 "/Hr Storm 0, Z cfs
Max. Discharge to Level Spreader /10 cfs
Filter Strip/ Zone 2 Buffer Vegetation (thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
• a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
Applicants Initials
a, Project Site was visited prior to designing level spreader.
Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
Pre-Formed Scour Holes are on flat slopes only.
If OW No structures are located in protected buffers (must meet no practical alternatives criteria).
Design Alternative (if any) and Bypass method used:
I-e Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
,O ? Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.
0
0
LEVEL
FOR E F

0
'in
1 l
'U
U-
•
0
FES 5
ByPass Channel Design
10-yr, 24 hour storm
Stonemont
Drainage Area
Intenstiy
Rational C
Impervious area
Forebay Area
Flow to level spreader
length of level spreader
Set min. length as 13'
Set flow through level spreader as
Estimate of Q10
Intensity
Q10
Flow through by-pass channel
Reach 1
Longitudim
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
0.44 acres
1 inch/hour
0.85
0.35 acres
31 cu.ft.
0.4 cfs
4.9 feet
1.0 cfs
7.22
2.7 cfs
1.7
5%
4.00 vert:horiz
0
0.035
0.375 feet
3.0 feet per second
1.17 Grass ok; provide lining for establishment
•
•
ROM STATION/REACH:
HYDRAULIC RESULTS
Discharge
cfs Peak Flow
Period hfx Velocity [fps] Area (sq.ft) Hydraulic
Radiusft Normal
Depth ft
P.7 0.5 2.17 0.78 0.21 0.44
NAGE AREA: FES
L- Bottom 1
4.0 Width = 0.00 It 4.0
LINER RESULTS
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psf) Shear Stress
(psf)
Straight S75 Unvegetated 1.55 1.38 1.12 STABLE
Staple D
Back to Input Screen
is
Permit Number:
(to be provided by DW
Drainage Area Number: M5 7
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will, be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
Once a year, soil pH willbe tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within. 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/debris.
system
The flow splitter device The flow splitter device is
k Unclog the conveyance and dispose
(if applicable) clo
ed. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
J
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
•

•
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The Swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The lr'vel lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otheFwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long
' Maintain grass at a height of
if a
licable . approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-t,evel Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(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: Stonemont
BMP drainage area number: E5
Print name: Curtis Jones Jr. .
Title: member
Address: 140 Towerview Court, Cm, NC
Phone:
Signz
Bate:
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, P 1S-rY L a Notary Public for the State
?'Y of
IL/44 CAMIle,w County of ,c , do hereby certify that
Jr personally appeared before me this 9 7W
day of , ZGo , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
My commission expires, y- Z?7 7Dl D
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Witness my hand and official seal,
• DWQ Project No.
DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
1. PROJECT INFORMATION (please complete the following information):
Project Name
Contact Person: Phone Number:
Level Spreader ID:
Level Spreader Length 1 3 ft. (perpendicular to flow)
Drainage Area D, 5-+ ac. (on-site and off-site drainage to the level spreader)
Impervious Area in, Ifs ac. (on-site and off-site drainage to the level spreader)
Forebay Area Tt?. cu ft. (0.2% of the contributing impervious surface area)
Maximum Filter Strip/Buffer Slope .4y 1) % (6% for forested, leaf littler cover, 8% for thick ground cover
grass
Max. Discharge from 1"/Hr Storm o, 3 cfs
Max. Discharge to Level Spreader 1,0 cfs
Filter Strip/ Zone 2 Buffer Vegetation (thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used
11. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
• requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
roject Site was visited prior to designing level spreader.
Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
?t?Lt ee Pre-Formed Scour Holes are on flat slopes only.
A* No structures are located in protected buffers (must meet no practical alternatives criteria).
Applicants Initials
P
7
Design Alternative (if any) and Bypass method used:
1 Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
A?l Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.
0
•

'U
•
0
• FES 7
Bypass Channel Design
10-yr, 24 hour storm
Stonemont
•
Drainage Area
Intenstiy
Rational C
Impervious area
Forebay Area
Flow to level spreader
length of level spreader
Set min. length as 13'
Set flow through level spreader as
Estimate of Q10
Intensity
Q10
Flow through by-pass channel
Reach 1
Longitudinc
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
0.54 acres
1 inch/hour
0.85
0.43 acres
38 cu.ft.
0.5 cfs
6.0 feet
1.0 cfs
7.22
3.3 cfs
2.3
5%
4.00 vert:horiz
0
0.035
0.42 feet
3.3 feet per second
1.31 Grass ok; provide lining for establishment
0
•
•
HYDRAULIC RESULTS
Discharge
cls Peak Flow
Period hrs Velocity [fps] Area (sq.ft) Hydraulic
Radius t Normal
Depth ft
2.3 0.5 3.28 0.70 0.20 542
LINER RESULTS
IEA: FES 7 IDESIGN FREQUENCY: 10-year
Unreinforced Vegetation (n=0.035)
S = 0.0500
1 L Bottom 1
4.0 Width = 0.00 It 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
Ipsf) Shear Stress
(psf)
Straight Unreinforced Vegetation D Mix 75-95Y 3.33 1.31 2.55 STABLE
Soil Sandy Loam 0.035 0.065 0.54 UNSTABLE
Back to Input Screen
0
•
•
ROM STATIDNIREACH:
HYDRAULIC RESULTS
Discharge
cfs Peak Flow
Period hrs Velocity (fps) Area (sq.ft) Hydraulic
Radiur[1t] Normal
De th ft
2.3 0.5 2.34 0.98 0.24 0.50
LINER RESULTS
1L ` / ?1
Bottom
4.0 Width = 0.00 ft 4.0
Not to Scale
10-year

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psf) Shear Stress
(psf)
Straight S75 Unvagetated 1.55 1.55 1.00 STABLE
Staple D
Back to Input Screen
0
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
• Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I 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.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will, be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The'flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
re air.
•
Form SWU40l-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
•
•

BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
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.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(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: Stonemont
BMP drainage area number: r?'E S
Print name: Curtis Jones Jr.
Title: member
Address: 140 Towerview Court, CM, NC
Phone:
Signati
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, 15T Y L ?c.4nn f? , a Notary Public for the State of
MI ZAD , County of do hereby certify that
(fut n&cs fI' • personally appeared before me this 9 7AI
day of ?U I ZpD , and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
My commission expires .kr- Z Y 7 p, 1 ?>
Form SWU401-Level Spreader, Filter'Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
DWQ Project No.
DIVISION OF WATER QUALITY - LEVEL SPREADER WORKSHEET (112007)
1. PROJECT INFORMATION (please complete the following information):
Project Name
Contact Person: Phone Number: fM
Level Spreader ID:
Level Spreader Length 3 _ ft. (perpendicular to flow)
Drainage Area ac. (on-site and off-site drainage to the level spreader)
Impervious Area ©t ac. (on-site and off-site drainage to the level spreader)
Forebay Area cu ft. (0.2% of the contributing impervious surface area)
Maximum Filter Strip/Buffer Slope 2.c)% % (6% for forested, leaf littler cover, 8% for thick ground cover
grass
Max. Discharge from 1"/Hr Storm M.'-s cfs
Max. Discharge to Level Spreader ' cfs
Filter Strip/ Zone 2 Buffer Vegetation f
(thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used 4iez
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
ADolicants Initials
IN16 Project Site was visited prior to designing level spreader.
Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.
01 Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
hlG /KGs Pre-Formed Scour Holes are on flat slopes only.
IfA No structures are located in protected buffers (must meet no practical alternatives criteria).
Design Alternative (if any) and Bypass method used:
Bypass conveyance method is specified and plan details and calculations are provided.
Alternative design option is specified and plan details and calculations are provided.
AA Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
APW No structures are located in protected buffers.
Plan details for the bypass and outlets are provided.
The operation and maintenance agreement includes annual erosion and vegetation repair.
The operation and maintenance agreement signed and notarized by the responsible party is provided.
0
•

.li)
•
0
• FES 7
Bypass Channel Design
10-yr, 24 hour storm
Stonemont
•
Drainage Area
Intenstiy
Rational C
Impervious area
Forebay Area
Flow to level spreader
length of level spreader
Set min. length as 13'
Set flow through level spreader as
Estimate of Q10
Intensity
Q10
Flow through by-pass channel
Reach 1
Longitudim
Side slopes:
Bottom with
Mannings n:
Depth of Flow:
Velocity
Tractive force
B&F Consulting, Inc.
2805 Tobermory Lane
Raleigh, NC 27606
[phone]
0.42 acres
1 inch/hour
0.85
0.34 acres
29 cu.ft.
0.4 cfs
4.6 feet
1.0 cfs
7.22
2.6 cfs
1.6
5%
4.00 vert:horiz
0
0.035
0.42 feet
2.2 feet per second
1.31 Grass ok; provide lining for establishment
0
•
•
HYDRAULIC RESULTS
Discharge
cfs Peak Flow
Period hrx Velocity (fps) Area (sq.ft) Hydraulic
Radius ft Normal
Depth ft
h.6 0.5 212 0.75 0.21 0.43
LINER RESULTS
IDESIGN FREQUENCY: 10 year
(n=0.035)
5 = 0.0200
1L ` ?1
Bottom
4.0 Width = 0.00 ft 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psf) Shear Stress
(psf)
Straight Umeinforced Vegetation D Mix 75-95X 3.33 0.54 6.15 STABLE
Soil Sandy Loam 0.035 0.027 1.30 STABLE
Back to Input Screen
0
•
•
HYDRAULIC RESULTS
0 ST
Discharge
cfs Peak Flow
Period hrs Velocity [fps] Area (sq.ft) Hydraulic
Radius ft Normal
Depth ft
1.6 0.5 1.52 1.05 0.25 0.51
LINER RESULTS
FES 8 ]DESIGN FREQUENCY: 10-year
S75 (n=0.055)
S = 0.0200
1 L Bottom 1
4.0 Width = 0.00 ft 4.0
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type
I Density
Shear Stress
(psf)
Shear Stress
(psf]
Straight S75 Unvegetated 1.55 0.64 2.42 STABLE
Staple D
Back to Input Screen
0
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