HomeMy WebLinkAbout20130576 Ver 1_More Info Received_20130903`GREEN ENGINEERING, P.L.L.C.
Engineers/Planners/Surveyors
303 Goldsboro Street East Post Office Box 609
Wilson, North Carolina 27893
Telephone (252) 237 -5365 Fax (252) 243 -7489
To NCDENR - DW
WeBSCaPe
1650 Mail Service Center
Valeigh, -
SI Z y s��ev s%
QCNOAGE $�i /j,/jjy(� 9�ti � /�2
WE ARE SENDING YOU: E❑Attached El Under separate cover via the following items:
E] Shop Drawings ElPrints Plans El Samples El Specifications
OCopy of letter Change order
LETTER OF TRANSMITTAL
Date
9/3/2013
JOB NO.
112108
ATTENTION
Ms. Annette Lucas
DESCRIPTION
RE:
Halifax County Sawmill
9/3/2013
DWQ #13 -0576
13 - o � �I LO
1
9/3/2013
COPIES
DATE
NO.
DESCRIPTION
1
9/3/2013
1
Full Sized set of plans showing drainage and storm water management
1
9/3/2013
2
BMP Suppleme nt Form for Ponds B and C
1
9/3/2013
3
10 & M Agreements for Ponds B and C
THESE ARE TRANSMITTED as checked below:
OFor approval
Approved as submitted
Approved as noted
Resubmit _copies for approval
DReturn _ corrected prints
E]For your use
Review and comment
[]As requested
Submit copies for distribution
Returned for corrections
Fol
REMARKS:
OFOR BIDS DUE 20 PRINTS RETURNED AFTER
LOAN TO US
COPY TO
If enclosures are not as noted, kindly notify us at once.
SIGNED
Sean P. Hein
Permit No.
(to be provided by DWQ)
�oF WA T§9P
O G�
NCDENR '
o
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 ChedrGst (Part 111) must be printed, filled out and submitted along with all of the required information.
1. PROJECT INFORMATION
Project name
l9ausner Lumber Two
Contact person
Sean Hein
Phone number
252 - 237 -5365
Data
7012013
Drainage area number
Pond B
Ii. DESIGN INFORMATION
Site Characteristics
Drainage area
39 f?
Impervious area, post -development
32 f?
% impervious
79.95%
Design rainfall depth
1.5 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5' runoff volume
Pre-development 1 -yr, 24-hr runoff
Post -development 1 -yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pretpost control of the 1yr 24hr storm peak flow required?
1 -yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post -development
Rainfall intensity: l -yr, 24-hr storm
Pre-development 1 -yr, 24-hr peak flow
Post -development 1 -yr, 24-hr peak flow
Pre/Post 1 -yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 10ft vegetated shelf elevation
Bottom of 10ft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state - required temp. pool?
Elevation of the top of the additional volume
107,158 ft3
162,904 ft3 OK, volume provided Is equal to or in excess of volume required.
ft3
tt
ft3
ft3
ft"
N (Y or N)
2.8 in
74.00 ( unitless)
85.00 (unitless)
1.50 in/hr OK
32.60 ft' /sec
48.14 ft3 /sec
15.54 ft3 /36c
92.00 fmsl
91.00 fmsl
91.00 fmsl
91.50 fmsl
90.50 hnsl
89.00 fmsl
88.00 fmsl
1.00 it
N (Y or N)
fmsl
Form SW401 -Wet Detention Basin- Rev.94/18/12 Parts 18 11 Design Summary, Page 7 of 2
Permit No.
(to be provded by DWO)
II. DESIGN INFORMATION
(Y or N)
Surface Areas
in
Area, temporary pool
106,206 If
Area REQUIRED, permanent pool
1 fe
SAIDA ratio
3.36 (unitless)
Area PROVIDED, permanent pool, Ap m_pw
58,189 fe OK
Area, bottom of 1Oft vegetated shelf, Abk_,w
51,108 fe
Area, sediment deanout, top elevation (bottom of pond), Ab,Lpw
40,782 fe
Volumes
0.5
Volume, temporary pool 162,904 fe
Volume, permanent pool, V,,_pw 142,123 fts
Volume, forebay (sum of forebays if more than one forebay) 28,500 113
Forebay % of permanent pool volume 20.1%%
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, V,,-,M
Area provided, permanent pool, A�, m_pw
Average depth calculated
Average depth used in SAIDA, d,,,, (Round to nearest 0.511)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, A,,,_pw
Area, bottom of 1011 vegetated shelf, Aw_#a
(Y or N)
N (Y or N)
3.36 (unitless)
Y (Y or N)
142,123 ft'
58,189 ft,
3.00 ft
3.0 It
N (Y or N)
58,189 fe
51,108 ft
Area, sediment deanout, top elevation (bottom of pond), AbLow 40,782 fe
'Depth' (distance b/w bottom of 1 Oft shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, da„ (Round to down to nearest 0.511)
Drewdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (d- non - dreular)
Coefficient of discharge (CD)
Driving head (H,)
Drawdown through weir?
Weir type
Coefficient of discharge (C„)
Length of weir (L)
Driving head (H)
Pre - development 1 -yr, 24-hr peak flow
Post -development 1 -yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
1.50 It
ft
ft
N
(Y or N)
10 :1
in
10.0 It
In'
5 :1
(unitiess)
1.6 :1
ft
Y
(Y or N)
SQUARE (unitiess)
3.33
(unitiess)
1
It
0.5
It
OK
32.60 fe/sec
GATE VALVE
48.14 felsec
1.26 fe/sec
2.00 days
160
OK
OK
OK
OK, draws down in 2 -5 days.
3 :1
OK
10 :1
OK
10.0 It
OK
5 :1
OK
1.6 :1
OK
Y (Y or N)
OK
1.0 It
OK
Y (Y or N)
OK
Y (Y or N)
OK
Y (Y or N)
OK
W DISCHARGE PIPE WITH
GATE VALVE
Forth SW401 -Wet Detention Basin- Rev.9. 4/18/12 Parts I.8 11 Design Summary, Page 2 of 2
Permit No.
(to be provided by DWQ)
III. 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.
Form SW401 -Wet Detention Basin- Rev.94/18/12 Part III. Required Items Checklist, Page 1 of 1
Pagel Plan
In s
Sheet No.
33
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.
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
/
s1 s
- Filter strip.
3. Section view of the wet 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, dean out of the basin is specified
on the plans prior to use as a wet detention basin.
7�_
S
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.
7. The supporting calculations.
AfMy
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
SUI��iP�
soil maps are not an acceptable source of soils information.
Form SW401 -Wet Detention Basin- Rev.94/18/12 Part III. Required Items Checklist, Page 1 of 1
4
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
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 present.
Remove the trash/ debris.
The perimeter of the wet
detention basin
Areas of bare soil and /or
erosive gullies have formed.
Regrade the soil if necessary to
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
I
Maintain vegetation at a height of
long.
approximately six inches.
Form SW401 -Wet Detention Basin O &M -Rev.4
Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
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.4 Page 2 of 4
4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
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. if applicable)
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 2.0 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 1.0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 91.0
Sediment Removal Ej. 90.0 Pe anen Pool
-------------- - - Volume Sediment Removal Elevation 89.0 Volume
Bottom Elevatio 89.0 -ft Min.
-------------------------------------- - - - - -- - - - - --
Sediment Bottom Elevation 88.0 1 -ft
Storage Sedimei
Storage
FOREBAY MAIN POND
Form SW401 -Wet Detention Basin O &M -Rev.4
Page 3 of 4
A
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:Klausner Lumber Two
BMP drainage area number:Pond B
Print name:
Title:
Address:
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.
1, rni be F rY )n g g�..t , a Notary Public for the State of
Qor,5, 0arolinn... , County of Ij I k , do hereby certify that
personally appeared before me this ao° h
day of PhA ,,,,,5 � , 0;0 3 and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
APPROVED AS TO FORN AND
LEWITr
a/L
Cu NTY ATTORN
My commission expires �Da- ca�S —c�C�l F
Form SW401 -Wet Detention Basin O &M -Rev.4
Page 4 of 4
Permit No.
(to be provided by DWO)
A�� 020E W a TF9pG
' y
NCDEW '
O T
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 Cheddist (Part 111) must be printed, filled out and submitted along with all of the required Information.
L PROJECT INFORMATION
Project name l9ausner Lumber Two
Contact person Sean Hein
Phone number 252 -237 -5365
Date 7/2612013
Drainage area number Pond C
Ill. DESIGN INFORMATION
Site Characteristics
Drainage area
Impervious area, post -development
% impervious
Design rainfall depth
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5' runoff volume
Pre-development 1 -yr, 24-hr runoff
Post - development 1 -yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the prelpost control of the 1 yr 24hr storm peak flow required?
1 -yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post - development
Rainfall Intensity: l -yr, 24-hr stone
Pre - development 1 -yr, 24-hr peak flow
Post -development 1 -yr, 24-hr peak flow
Pre/Post 1 -yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of l Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment deanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state - required temp. pool?
Elevation of the top of the additional volume
67 f?
53 fe
80.00%
1.5 in
202,722 ft3
289,664 ft3 OK, volume provided Is equal to or in excess of volume required.
ft3
ft
ft3
ft3
N (Y or N)
2.8 in
74.00 (unitless)
85.00 (unitless)
1.50 In/hr OK
35.10113 1sec
117.70 ft3 /sec
82.60 ff Isec
89.50 fmsl
88.00 fmsl
88.00 fmsl
88.50 fmsl
87.50 fmsl
86.00 fmsl
85.00 fmsl
1.00 ft
N (Y or N)
fmsl
Form SW401 -Wet Detention Basin -Rev 94118/12 Parts 18 11 Design Summery, Page 1 of 2
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool 187,910 ft
Area REQUIRED, permanent pool 1 fl?
SAIDA ratio 2.00 ( unitiess)
Area PROVIDED, permanent pool, Ap,,,,,yw 101,452 If OK
Area, bottom of 10ft vegetated shelf, AboL&O 92,205 it'
Area, sediment cieanout, top elevation (bottom of pond), Ab,Lpm 78,635 ft'
Volumes
Volume, temporary pool 289,664 ft3 OK
Volume, permanent pool, Vp.._,w 181,183 ft3
Volume, forebay (sum of forebays if more than one forebay) 36,237 ft3
Forebay % of permanent pool volume 20.0%% OK
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, Vm_pw
Area provided, permanent pool, Ap m_,„ i
Average depth calculated
Average depth used in SAIDA, d. (Round to nearest 0.511)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, A,,,,,_p„ 1
Area, bottom of 1 Oft vegetated shelf, AboLw a
Area, sediment cleanout, top elevation (bottom of pond), Abo v w
%
(Y or N)
N (Y or N)
2.00 (unitless)
Y (Y or N)
181,183 fe
101,452 ft
3.00 ft OK
3.0 ft OK
N (Y or N)
101,452 fe
92,205 ft`
78,635 ft2
'Depth' (distance b/w bottom of 1011 shelf and top of sediment) 1.50 ft
Average depth calculated ft
Average depth used in SAIDA, d. (Round to down to nearest 0.5ft) ft
Drawdown Calculations
Drawdown through oriRoe?
Diameter of orifice (if circular)
Area of orifice (if -non- circular)
Coefficient of discharge (Co)
Driving head (H,)
Drawdown through weir?
Weir type
Coefficient of discharge (C„ )
Length of weir (L)
Driving head (H)
Pre - development 1 -yr, 24-hr peak flow
Post - development 1 -yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build -out?
Drain mechanism for maintenance or emergencies is:
N (Y or N)
in
In
( unitless)
ft
Y (Y or N)
SQUARE ( unitiess)
3.33 (unitless)
1 ft
0.5 ft
35.10 ft?/sec
117.70 f3 /sec
1.26 f?/sec
2.00 days
OK, draws down in 2 -5 days.
3 :1 OK
10 :1 OK
10.0 It
OK
5 :1
OK
1.6 :1
OK
Y (Y or N)
OK
1.0 ft
OK
Y (Y or N)
OK
Y (Y or N)
OK
Y (Y or N)
OK
8' DISCHARGE PIPE WITH
GATE VALVE
Permit No.
(to be provided by DWQ)
Form SW401 -Wet Detention Basin- Rev.94/18/12 Parts I. & 11. Design Summary. Page 2 of 2
Permit No.
(to be provided by D W6)
Ill. 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.
Form SW401 -Wet Detention Basin- Rev.9- 4118/12 Part III. Required Items Checklist, Page 1 of 1
Pagel Plan
s
Sheet No.
33
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 (ROW),
- Overflow device, and
- Boundaries of drainage easement.
tr
G
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
- Fifter strip.
S7- s!7
3. Section view of the wet detention basin (1' = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
-Inlet and outlet structures.
C���'S`
4. If the basin is used for sediment and erosion control during construction, dean out of the basin is specified
on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
14
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.
Slp/�
0"A 116del
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (0 &M) agreement.
SAN
AA
9. A copy of the deed restrictions (if required).
40-1
P 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.9- 4118/12 Part III. Required Items Checklist, Page 1 of 1
i
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
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 present.
Remove the trash/ debris.
The perimeter of the wet
detention basin
Areas of bare soil and /or
erosive gullies have formed.
Regrade the soil if necessary to
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
lonR. I
approximately six inches.
Form SW401 -Wet Detention Basin O &M -Rev.4
Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
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.4
Page 2 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
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. if applicable)
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 2.0 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 1.0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
0 Permanent Pool Elevation 88.0
Sediment Removal . 87.0 Pe anen Pool
-------------- - - Volume Sediment Removal Elevation 86.0 Volume
Bottom Elevatio 86.0 -ft Min. ------------------------------- ------ - - - - - -- - - ----
Sediment Bottom Elevation 85.0 1 -ft
Storage Sedimei
Storage
FOREBAY MAIN POND
Form SW401 -Wet Detention Basin O &M -Rev.4
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:Klausner Lumber Two
BMP drainage area number:Pond C
Print name: -Too i[n
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.
1, & ur p iA e� F. (Yl a -P 25 , a Notary Public for the State of
NorON C p r-n 1: nr_ , County of t b 1% -Qk x , do hereby certify that
"Tony rr> L-0 0 personally appeared before me this �
day of Auav�s� , _ oN5 , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires Oa- ? -,
Form SW401 -Wet Detention Basin O &M -Rev.4
APPROVED AS 10 FINN AND
MALITY
NICXHT AiiONNEY
Page 4 of 4