20220398 Ver 3_Mitchell County MS O&M Plan_20230301

'44D Civil
Design
Concepts, PA
Mitchell County Middle School
NCDEQ Project: DWR 223-0398
Stormwater Control Management System Description
Mitchell County Middle School (NCDEQ Project: DWR 223-0398) is a 14.93± acre school campus located
at 5085 South NC Highway 226, Bakersville, NC 28705. The project will collect stormwater runoff from
building roofs, pavement, ditched, and grassed areas through various drainage inlets consisting of curb
inlets, yard inlets, junction boxes, etc.
Conveyance of stormwater runoff will be achieved using a system of HPDE storm pipes (varying in size)
and/or permanent diversion ditches. Basic maintenance and operation of these conveyances will include
regular cleaning of trash and debris, careful observation of performance and function, and if necessary,
landscaping/regrading or repair of damaged elements. For natural conveyance channels, adequate
vegetation must be established and maintained to provide appropriate operation and functionality.
The drainage inlet devices and conveyance structures will direct stormwater runoff to the onsite
treatment system. The proposed onsite stormwater treatment system includes the following SCM:
- One (1) Wet Detention Basin
The wet detention basin is defined as a wet pond designed to capture the design storm
and release it slowly over a period of time through a design outlet structure. This SCM
was designed to NCDEQ standards and functions primarily through dilution and
settling of stormwater.
Operation and maintenance of the aforementioned SCM, conveyance, and all other inlet/outlet control
structures associated with the project will be completed according to the NCDEQ Stormwater Design
Manual.
Planning documents and calculations for the design and construction of the proposed stormwater
management system have been provided and can be reproduced upon request.

Project Name: Mitchell County Middle School
Project Location: 5085 South NC Highway 226
'N 1E
IRCover 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 or
Infiltration Basin
Quantity:
Infiltration Trench
Quantity:
Bioretention Cell
Quantity:
Wet Pond
Quantity:
1
Stormwater Wetland
Quantity:
Permeable Pavement
Quantity:
Sand Filter
Quantity:
Rainwater Harvesting
Quantity:
Green Roof
Quantity:
Level Spreader - Filter Strip
Quantity:
Proprietary System
Quantity:
Treatment Swale
Quantity:
Dry Pond
Quantity:
Disconnected Impervious Surface
Present:
No
User Defined SCM
Present:
No
Low Density
Present:
No
O&M sheets will I
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Type:
ie aaaea automaticai
On Site
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.
Signature:
Responsible Party:
Title & Organization:
Street address. -
City, state, zip:
Phone number(s):
Email. -
Mitchell County School District
Executive Director -Career Tech. EducationlFacilities/Athleties
72 Ledger School Road
Bakersville, NC 28706
828-766-3437
[e-mail]
_ Date: '
a Notary Public for the State of �)Ur-F-, „n4�
County of M� ktIn 4P_ 1 j do hereby certify that k ,•em a C�S ir�G �1
personally appeared before me this dayof 26�'l3 and
acknowledge the due execution of the Operations and Maintenance Agreement .
Witness my hand and official seals
Seal
ROBIN STREET
NOTARY PUBLIC
Mitchsll County
North Carolina
My Commission Expire$ March 2, 2027
My commission expires , . a- 2�

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
OJECT INFORMATION
1 Project Name
Mitchell County Middle School
2 Project Area ac
14.63
3 Coastal Wetland Area ac
NA
4
Surface Water Area ac
0.3
5
Is this project High or Low Density?
High
6
1 Does this project use an off -site SCM?
No
COMPLIANCE WITH 02H .1003(4)
7
Width of vegetated setbacks provided feet
30
8
Will the vegetated setback remain vegetated?
Yes
9
If BUA is proposed in the setback, does it meet NCAC 02H.1003 4 c-d ?
N/A
10
Is streambank stabilization proposed on this project?
No
NUMBER AND TYPE OF SCMs:
11
Infiltration System
12
Bioretention Cell
13
Wet Pond
1
14
Stormwater Wetland
15
Permeable Pavement
16
Sand Filter
17
lRainwater Harvesting RWH
18
Green Roof
19
Level Spreader -Filter Strip LS-FS
20
Disconnected Impervious Surface DIS
21
Treatment Swale
22
Dry Pond
23
StormFilter
24
Silva Cell
25
Bayfilter
26
1 Filterra
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Michael Cain, PE
28
Organization:
Civil Design Concepts
29
Street address:
168 Patton Avenue
30
City, State, Zip:
Asheville, NC 28801
31
Phone numbers :
828-252-5388
32
Email:
[e-mail]
Certification Statement:
I certify, under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision; that the
information provided in the form is, to the best of my knowledge and belief, true, accurate, and complete; and that the engineering plans,
specifications, operation and maintenance agreements and other supporting information are consistent with the information provided here.
CARO
E SI0 .. F/
SEAL -
047788
FNG INEE�
AEL J•G
Signature AVesigner
1� C;l ZIOZ_
D to

DRAINAGE AREAS
1
Is this a high density project?
Yes
2
If so, number of drainage areas/SCMs
1
3
Does this project have low density areas?
No
4
If so, number of low density drainage areas
0
5
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
DRAINAGE AREA INFORMATION
Entire Site
1
4
Type of SCM
Wet Pond
5
Total drainage area (sq ft
329314
6
Onsite drainage area (sq ft)
325292
7
Offsite drainage area (sq ft
4022
8
Total BUA in project (sq ft
154202 sf
9
New BUA on subdivided lots (subject to permitting)
(sq ft
NA
10
New BUA not on subdivided lots (subject to
permitting) (so
Offsite BUA (sq ft)
Breakdown of new BUA not on subdivided lots:
Parking (sq ft
Sidewalk (sq ft
154202 sf
11
NA
12
48007 sf
9872 sf
Roof (sq ft
67783 sf
Roadway (sq ft)
24366 sf
Future (sq ft
NA
Other, please specify in the comment box
below (sq ft)
4174 sf
13
New infiltrating permeable pavement on
subdivided lots (sq ft
NA
14
New infiltrating permeable pavement not on
subdivided lots (sq ft)
Existing BUA that will remain (not subject to
s ft
NA
15permitting)
NA
16
Existing BUA that is already permitted (sq ft)
4792 sf
17
Existing BUA that will be removed (sq ft
4792 sf
18
Percent BUA
47%
19
IDesign storm inches
3.3 in
20
Design volume of SCM cu ft
32541 cf
21 Calculation method for design volume
DITIONALOYFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):
Other impervious includes outdoor court
SA/DA

WET POND
1
Drainage area number
1
2
1 Minimum required treatment volume cu ft
15094 cf
GENERAL MDC FROM 02H .1050
3
Is the SCM sized to treat the SW from all surfaces at build -out?
Yes
4
Is the SCM located away from contaminated soils?
Yes
5
What are the side slopes of the SCM (H:V)?
3:1
6
Does the SCM have retaining walls, gabion walls or other engineered
side slopes?
No
7
Are the inlets, outlets, and receiving stream protected from erosion
(10-year storm)?
Yes
8
Is there an overflow or bypass for inflow volume in excess of the
design volume?
Yes
9
What is the method for dewatering the SCM for maintenance?
Drawdown Orifice
10
If applicable, will the SCM be cleaned out after construction?
Yes
11
Does the maintenance access comply with General MDC (8)?
Yes
12
Does the drainage easement comply with General MDC 9 ?
Yes
13
If the SCM is on a single family lot, does (will?) the plat comply with
General MDC (10)?
Yes
14
Is there an O&M Agreement that complies with General MDC (11)?
Yes
15
Is there an O&M Plan that complies with General MDC 12 ?
Yes
16
Does the SCM follow the device specific MDC?
Yes
17
Was the SCM designed by an NC licensedprofessional?
Yes
WET POND
MDC FROM 02H .1053
18
Sizing method used
SA/DA
19
Has a stage/storage table been provided in the calculations?
Yes
20
Elevation of the excavated main pool depth (bottom of sediment
removal) (fmsl
2719.00
21
Elevation of the main pool bottom (top of sediment removal) (fmsl)
2720.00
22
Elevation of the bottom of the vegetated shelf fmsl
2725.00
23
Elevation of the permanent pool (fmsl)
2725.00
24
Elevation of the top of the vegetated shelf (fmsl)
2726.00
25
Elevation of the temporary pool (fmsl)
2726.10
26
Surface area of the main permanent pool (square feet)
8909
27
Volume of the main permanent pool cubic feet
32541 cf
28
Average depth of the main pool feet
5.00 ft
29
Average depth equation used
Equation 2
30
If using a uation 3, main pool perimeter feet
31
If using equation 3, width of submerged veg. shelf (feet)
32
Volume of the forebay cubic feet
6404 cf
33
Is this 15-20% of the volume in the main pool?
Yes
34
Clean -out depth for forebainches
12in
35
Design volume of SCM cu ft
15094 cf
36
Is the outlet an orifice or a weir?
Orifice
37
If orifice, orifice diameter inches
3 in
38
If weir, weir height (inches)
39
If weir, weir length inches
40
Drawdown time for the temporary pool (days)
2.4
41
Are the inlet(s) and outlet located in a manner that avoids short-
circuiting?
Yes
42
Are berms or baffles provided to improve the flow path?
Yes
43
Depth of forebay at entrance (inches)
48 in
44
Depth of forebay at exit (inches)
36 in
45
Does water flow out of the forebay in a non -erosive manner?
Yes
46
Width of the vegetated shelf (feet)
6 ft
47
Slope of vegetated shelf (H:V)
6:1
48
Does the orifice drawdown from below the top surface of the
permanentpool?
Yes
49
Does the pond minimize impacts to the receiving channel from the 1-
r, 24-hr storm?
Yes
50
Are fountains proposed? (If Y, please provide documentation that
MDC 9 is met.
No
51
Is a trash rack or other device provided to protect the outlet system?
Yes
52
Are the dam and embankment planted in non -clumping turf grass?
Yes
53
Species of turf that will be used on the dam and embankment
Fescue
541
Hasa planting plan been provided for the vegetated shelf?
Yes
ADDITIONAL INFORMATION
55
Please use this space to provide any additional information about the
wet pond(s):
Wet Pond 1 10:40 AM 1/5/2023

'44D Civil
Design
Concepts, PA
Wet Pond Operation and Maintenance Manual
The Property Owner should keep a maintenance record on this SCM. This maintenance record
will be kept in a log in a known set location. Any deficient SCM elements noted in the
inspection should be corrected, repaired, or replaced immediately. These deficiencies can affect
the integrity of structures, safety of the public, and the removal efficiency of the SCM.
The wet pond detention system is defined as a permanent pool of water that removes TSS
through dilution and settling. A wet pond is designed to capture the design storm and
release it slowly over a period of 2-5 days. The wet detention basin and pretreatment
includes the forebay.
Important maintenance procedures:
- Immediately after the wet pond 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 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 pond.
- If the basin must be drained for an emergency or to perform maintenance, the pond
should be drained by a pump with a floating inlet to prevent discharge of sediment to
the maximum extent practical.
- Triennially an inspection will be performed by an Engineer.
- Once a year, a dam safety expert should inspect the embankment.
- The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate
accumulated sediments.
After the wet 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. Projected maintenance budget over a 20-year plan is approximately $50,625
(including a 25% contingency).
Inspection activities shall be performed as follows. Any problems that are found shall be
repaired immediately.

SCM Element:
Potential Problems:
How I will remediate the problem:
The entire SCM
Trash/debris are present
Remove the trash/debris
The perimeter of the wet pond
Areas of bare soil and/or
Regrade the soil if necessary to
erosive gullies have formed.
remove the gully, plant ground
cover and water until it is
established. Provide lime and a
one-time fertilizer application
The inlet pipe is clogged (if
Unclog the pipe. Dispose of the
The inlet device
applicable)
sediment in a location where it will
not cause impacts to streams or the
SCM.
The inlet pipe is cracked or
Repair or replace the pipe.
otherwise damaged (if
applicable)
Erosion is occurring in the
Regrade the swale if necessary and
swale (if applicable)
provide erosion control devices
such as reinforced turf matting or
riprap to avoid future erosion
problems.
Sediment has accumulated to
Search for the source of the
The forebay
a depth greater than the
sediment and remedy the problem
original design depth for
if possible. Remove the sediment
sediment storage.
and dispose of it in a location
where it will not cause impacts to
streams or the SCM.
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.
Mailing Address: P.O. Box 5432, Asheville, NC 28813
168 Patton Avenue Asheville, NC 28801 52 Walnut Street — Suite 9, Waynesville, NC 28786
Phone [phone] Fax [phone] Phone: [phone] Fax: [phone]
Page 2 of 4

SCM Element:
Potential Problems:
How I will remediate the problem:
Best professional practices
Prune according to best
The vegetated shelf
show that pruning is needed
professional 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.
Sediment has accumulated to
Search for the source of the
The main treatment area
a depth greater than the
sediment and remedy the problem
original design sediment
if possible. Remove the sediment
storage depth.
and dispose of it in a location
where it will not cause impacts to
streams or the SCM.
Algal growth covers over 50%
Consult a professional to remove
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.
Shrubs have started to grow
Remove shrubs immediately
The embankment
on the embankment
Evidence of muskrat or
Consult a professional to remove
beaver activity is present
muskrats or beavers and repair any
holes or erosion.
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,
immediately.
shows that the embankment
needs repair.
Mailing Address: P.O. Box 5432, Asheville, NC 28813
168 Patton Avenue Asheville, NC 28801 52 Walnut Street — Suite 9, Waynesville, NC 28786
Phone [phone] Fax [phone] Phone: [phone] Fax: [phone]
Page 3 of 4

SCM Element:
Potential Problems:
How I will remediate the problem:
Clogging has occurred.
Clean out the outlet device and
dispose of any sediment in a
The outlet device
location where it will not cause
impacts to streams or the SCM
The outlet device is damaged
Repair or replace the outlet device.
Weeds or volunteer trees are
Remove weeds or trees.
Floating wetland island (if
growing on the mat.
applicable)
The anchor cable is damaged,
Restore the anchor cable to its
disconnected, or missing.
design state.
Erosion or other signs of
Repair the damage and improve
damage have occurred at the
the flow dissipation structure.
The receiving water
outlet.
Discharges from the wet pond
Contact the local NCDEQ Regional
are causing erosion or
Office.
sedimentation in the receiving
water.
Mailing Address: P.O. Box 5432, Asheville, NC 28813
168 Patton Avenue Asheville, NC 28801 52 Walnut Street — Suite 9, Waynesville, NC 28786
Phone [phone] Fax [phone] Phone: [phone] Fax: [phone]
Page 4 of 4

lddlbkL
cacGWRI
Cor�epts PA
COST ESTIMATE
20 Year Maintenance
MITCHELL COUNTY MIDDLE SCHOOL
02/28/2023
UNIT oTy
UNIT COST
TOTAL AMOUNT
DETENTIONWET
1 Stormwater Inspection Every 3 Years
2 Annual Dam Inspection
EA 7
EA 20
$1,500
$1,500
SUBTOTAL
$10,500
$30,000
$40,500
SUBTOTAL
$40,500
CONTINGENCY (25%)
$10,125
TOTAL
$50,625
ESTIMATED BY: MJC CDC PROJECT NO.: 12208