SW6231002_O&M Agreement/Plan_20231031

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Operation & Maintenance Agreement
Project Name: Serenity - Phases 8 & 9
Project Location: Rollins Rd., Harnett Co., NC
Cover Page
Maintenance records shall be kept on the following SCM(s). This maintenance record shall be kept in a log in a known set location.
Any deficient SCM 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 pollutant removal efficiency of the SCM(s).
The SCM(s)on this project include(check all that apply&corres•onding O&M sheets will be added automaticall :
Infiltration Basin Quantity:- Location(s):
Infiltration Trench Quantity:" Location(s):
Bioretention Cell Quantity:- Location(s):
Wet Pond Quantity: 6 Location(s): 35.55163,-78.83281
Stormwater Wetland Quantity: Location(s):
Permeable Pavement Quantity:- Location(s):
Sand Filter Quantity:- Location(s):
Rainwater Harvesting Quantity:- Location(s):
Green Roof Quantity:- Location(s):
Level Spreader-Filter Strip Quantity:- Location(s):
Proprietary System Quantity: Location(s):
Treatment Swale Quantity: 2 Location(s):
Dry Pond Quantity: Location(s):
Disconnected Impervious Surface Present: No Location(s):
User Defined SCM Present: No Location(s):
Low Density Present: No Type:
I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for
each SCM above,and attached O&M tables. I agree to notify NCDEQ of any problems with the system or prior to any changes to
the system or responsible party.
Responsible Party:Yang Song
Title&Organization: Greenfield Serenity LLC
Street address: 8601 Six Forks Road Suite 270
City,state,zip: Raleigh,NC 27615
Phone number(s): 919.815.6469
Email: [e-mail]
Signature: Date: ! ` /
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L IASa nnt. 1 • Lem(pka,- , a Notary Public for the State of AJO- r 1 Cc ra
County of CI�Q,�LL� , do hereby certify that Val
Soii
personally appeared before me this I(`Fh 1-
day of S� 4.mb-er tap�,3 and
acknowledge the due execution of the ations and ai enan Agreement.
Witness_ov.myyha6l,i,and official seal, Gt//I(.2_ ^ e..-
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STORM-EZ 8/3/2023
Version 1.5 O&M Agreement Page 1 of 6

Wet Pond Maintenance Requirements
Important operation and 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 pond should be fertilized after the initial fertilization that is required to establish
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the plants on the vegetated shelf.
Stable groundcover will be maintained in the drainage area to reduce the sediment load to the wet
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pond.
If the pond must be drained for an emergency or to perform maintenance, the flushing of sediment
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through the emergency drain will be minimized as much as possible.
At least once annually, a dam safety expert will inspect the embankment. Any problems that are
- found will be repaired immediately.
_ 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.
After the wet pond is established, it will be inspected quarterly 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 shall be kept in a
known set location and shall be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately.
SCM element: Potential problem: How to remediate the problem:
The entire wet pond Trash/debris is present. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to remove the gully, plant ground
pond erosive gullies have cover and water until it is established. Provide lime and a one-
formed. time fertilizer application.
The inlet pipe is clogged (if Unclog the pipe. Dispose of the sediment off-site.
applicable).
The inlet pipe is cracked or
otherwise damaged (if Repair or replace the pipe.
The inlet device applicable).
Erosion is occurring in the Regrade the swale if necessary and provide erosion control
swale (if applicable). devices such as reinforced turf matting or riprap to avoid future
problems with erosion.
Sediment has
accumulated to a depth Search for the source of the sediment and remedy the problem
greater than the original if possible. Remove the sediment and dispose of it in a location
design depth for sediment where it will not cause impacts to streams or the SCM.
storage.
The forebay
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.
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Version 1.5 O&M Agreement Page 2 of 6

Wet Pond Maintenance Requirements (Continued)
SCM element: Potential problem: How to remediate the problem:
Sediment has
accumulated to a depth Search for the source of the sediment and remedy the problem
greater than the original if possible. Remove the sediment and dispose of it in a location
design sediment storage where it will not cause impacts to streams or the SCM.
depth.
The main treatment area Algal growth covers over Consult a professional to remove and control the algal growth.
50% of the area.
Cattails, phragmites or
other invasive plants cover Remove the plants by wiping them with pesticide (do not spray).
50% of the basin surface.
Best professional practices
show that pruning is Prune according to best professional practices.
needed to maintain
optimal plant health.
The vegetated shelf Determine the source of the problem: soils, hydrology, disease,
Plants are dead, diseased etc. Remedy the problem and replace plants. Provide a one-
or dying. 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.
Shrubs have started to Remove shrubs immediately.
grow on the embankment.
Evidence of muskrat or Consult a professional to remove muskrats or beavers and
beaver activity is present. repair any holes or erosion.
The embankment A tree has started to grow Consult a dam safety specialist to remove the tree.
on the embankment.
An annual inspection by
an appropriate
professional shows that Make all needed repairs immediately.
the embankment needs
repair.
Clogging has occurred. Clean out the outlet device and dispose of any sediment in a
gg g location where it will not cause impacts to streams or the SCM.
The outlet device
The outlet device is Repair or replace the outlet device.
damaged.
Weeds or volunteer trees Remove the weeds or trees.
are growing on the mat.
Floating wetland island
(if applicable) The anchor cable is
damaged, disconnected or Restore the anchor cable to its design state.
missing.
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Version 1.5 O&M Agreement Page 3 of 6

Wet Pond Maintenance Requirements (Continued)
SCM element: Potential problem: How to remediate the problem:
Erosion or other signs of
damage have occurred at Repair the damage and improve the flow dissipation structure.
the outlet.
The receiving water Discharges from the wet
pond are causing erosion Contact the local NCDEQ Regional Office.
or sedimentation in the
receiving water.
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Version 1.5 O&M Agreement Page 4 of 6

Wet Detention Pond Design Summary
Wet Pond Diagram
WET POND ID FOREBAY MAIN POND
SCM 6 Permanent Pool El. 327.5 Permanent Pool El. 327.5
Temporary Pool El: 330 Temporary Pool El: 330
Pretreatment other No Clean Out Depth: 3.5 Clean Out Depth: 3.5
than forebay? Sediment Removal El 324 Sediment Removal El 322
Has Veg. Filter? No Bottom Elevation: 323 Bottom Elevation: 321
WET POND ID FOREBAY MAIN POND
SCM 7 Permanent Pool El. 328.5 Permanent Pool El. 328.5
Temporary Pool El: 330.5 Temporary Pool El: 330.5
Pretreatment other Clean Out Depth: 3.5 Clean Out Depth: 3.5
than forebay? No Sediment Removal El 325 Sediment Removal El 325
Has Veg. Filter? Bottom Elevation: 324 Bottom Elevation: 324
WET POND ID FOREBAY MAIN POND
SCM 8 Permanent Pool El. 352.5 Permanent Pool El. 352.5 j
Temporary Pool El: 355 Temporary Pool El: 355
Pretreatment other No Clean Out Depth: 3.5 Clean Out Depth: 3.5
than forebay? Sediment Removal El 349 Sediment Removal El 349
Has Veg. Filter? Bottom Elevation: 348 Bottom Elevation: 348
WET POND ID FOREBAY MAIN POND
SCM 9 Permanent Pool El. 362.5 Permanent Pool El. 362.5
Temporary Pool El: 364.25 Temporary Pool El: 364.25
Pretreatment other No Clean Out Depth: 3.5 Clean Out Depth: 3.5
than forebay? Sediment Removal El 359 Sediment Removal El 359
Has Veg. Filter? Bottom Elevation: 358 Bottom Elevation: 358
WET POND ID FOREBAY MAIN POND
SCM 10 Permanent Pool El. 370.5 Permanent Pool El. 370.5
Temporary Pool El: 372.25 Temporary Pool El: 372.25
Pretreatment other No Clean Out Depth: 3.5 Clean Out Depth: 3.5
than forebay? Sediment Removal El 367 Sediment Removal El 367
Has Veg. Filter? Bottom Elevation: 366 Bottom Elevation: 366
WET POND ID FOREBAY MAIN POND
SCM 11 Permanent Pool El. 376.5 Permanent Pool El. 376.5
Temporary Pool El: 378.5 Temporary Pool El: 378.5
Pretreatment other No Clean Out Depth: 3.5 Clean Out Depth: 3.5
than forebay? Sediment Removal El 373 Sediment Removal El 373
Has Veg. Filter? Bottom Elevation: 372 Bottom Elevation: 372
ATTACH ADDITIONAL SHEETS IF NECESSARY
STORM-EZ 8/3/2023
Version 1.5 O&M Agreement Page 5 of 6

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Treatment Swale Maintenance Requirements
Important operation and maintenance procedures:
_ The drainage area of the grassed swale will be carefully managed to reduce the sediment load to the
grassed swale.
_ After the initial fertilization to establish the grass in the swale, fertilizer will not be applied to the
treatment swale.
The grassed swale will be inspected quarterly. Records of operation and maintenance shall be kept in a known set
location and shall be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately.
SCM element: Potential problem: How to remediate the problem:
Trash/debris is present. Remove the trash/debris.
Areas of bare soil and/or Regrade the soil if necessary to remove the gully, re-sod (or plant
erosive gullies have with other appropriate species) and water until established.
formed. Provide lime and a one-time fertilizer application.
Sediment covers the grass Remove sediment and dispose in an area that will not impact
at the bottom of the swale. streams or SCMs. Re-sod if necessary.
The entire length of the Vegetation is too short or Maintain grassed vegetation such that the swale or vegetated
swale too long. area does not erode during the peak flow from the 10-year storm
Grass is dead, diseased or Determine the source of the problem: soils, hydrology, disease,
dying. etc. Remedy the problem and replace plants. Provide a one-time
fertilizer application to establish the ground cover if necessary.
Trees and/or other woody Remove the trees and woody vegetation from the treatment
vegetation are present in swale, regrade the treatment swale if necessary and re-establish
the treatment swale. grass as shown on the approved plans.
Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site.
The outlet device (if
applicable)
The outlet device is Repair or replace the outlet device.
damaged
Erosion or other signs of
damage have occurred at Repair the damage and improve the flow dissipation structure.
the outlet.
The receiving water Discharges from the
treatment swale are
causing erosion or Contact the local NCDEQ Regional Office.
sedimentation in the
receiving water.
STORM-EZ 8/3/2023
Version 1.5 O&M Agreement Page 6 of 6