SW6230401_O&M Agreement/Plan_20230707

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
- the plants on the vegetated shelf.
Stable groundcover will be maintained in the drainage area to reduce the sediment load to the wet
- pond.
If the pond must be drained for an emergency or to perform maintenance, the flushing of sediment
- 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
applicable). Unclog the pipe. Dispose of the sediment off-site.
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.
Remove the weeds, preferably by hand. If pesticide is used,
Weeds are present. wipe it on the plants rather than spraying.

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
50% of the area. Consult a professional to remove and control the algal growth.
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 needed to Prune according to best professional practices.
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
on the embankment. Consult a dam safety specialist to remove the tree.
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
damaged. Repair or replace the outlet device.
Weeds or volunteer trees
are growing on the mat. Remove the weeds or trees.
Floating wetland island
(if applicable) The anchor cable is
damaged, disconnected or Restore the anchor cable to its design state.
missing.

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.

Wet Detention Pond Design Summary
Wet Pond Diagram
WET POND ID FOREBAY MAIN POND
1 Permanent Pool El. 370.5 Permanent Pool El. 370.5
Temporary Pool El: 371.5 Temporary Pool El: 371.5
Pretreatment other Clean Out Depth: 2.5 Clean Out Depth: 6
than forebay? No Sediment Removal El 368 Sediment Removal El 364.5
Has Veg. Filter? No Bottom Elevation: 367 Bottom Elevation: 363.5
ATTACH ADDITIONAL SHEETS IF NECESSARY