SW6220601_Plansheet C12.5 - SCM Detail_20220629

PROJECT INFORMATION:
PROJECT LOCATED IN PHASE II AREA
RIVER BASIN: CAPE FEAR
WATERSHED DISTRICT: NA
FLOOD ZONE: MINIMAL FLOOD RISK AS PER DFIRM 37085 C PANEL 9588
WETLANDS: DELINEATED BY HAL OWEN & ASSOCIATES (2-9-2021) AS SHOW IN PLANS.
WON'T BE DISTURBED.
SOILS: MOSTLY SANDY AS SHOWN IN SHEET C11.4
THE SITE IS MOSTLY WOODLANDS.
WETLANDS
PROJECT IS LOW DENSITY. STORMWATER WILL BE MANAGED BY CONVEYANCE SWALES ALONG THE
ROADS AND DISPERSED FLOW IN THE LOTS.
TWO DRY PONDS WILL BE INSTALLED TO REDUCE THE POST -DEVELOPMENT FLOW
IN ACCORDANCE WITH TITLE 15 NCAC 2H.1000 AND S.L. 2006-246, THE
STORMWATER MANAGEMENT REGULATIONS, DEED RESTRICTIONS AND
PROTECTIVE COVENANTS ARE REQUIRED FOR LOW DENSITY RESIDENTIAL
SUBDIVISIONS WHERE LOTS WILL BE SUBDIVIDED AND SOLD. DEED
RESTRICTIONS AND PROTECTIVE COVENANTS ARE NECESSARY TO ENSURE
THAT THE DEVELOPMENT MAINTAINS A "BUILT -UPON" AREA CONSISTENT
WITH THE APPLICABLE REGULATION GOVERNING THE DENSITY LEVEL.
Conveyance Swale Design Information based on th 10 yr-storm -Magnolia Ridge
Swale
No.
Drainage
Area ac
Impervious
Area ac
Pervious
Area (ac)
C
Q (cfs)
Slope (%)
V allow
(f s
Vactual
(fps)
Flow Depth
ft
Type
Side Slope
Bottom
Width ft
Freeboard
(ft)
Top Width
ft
Liner
1
0.30
0.15
0.15
0.61
1.4
6.5
4.5
1.64
0.5
TRI
4:1
0
0.5
8.00
NC Green C125
2
0.23
0.14
0.09
0.55
1.00
6.50
4.50
1.25
0.65
TRI
4:1
0
0.5
7.80
Excelsior Mat
3
0.12
0.07
0.05
0.57
0.54
1.13
4.50
0.41
0.60
TRI
4:1
0
0.5
8.80
Excelsior Mat
4
0.12
0.07
0.05
0.57
0.54
1.13
4.50
0.41
0.60
TRI
4:1
0
0.5
8.80
Excelsior Mat
5
0.32
0.13
0.08
0.55
0.56
0.93
4.50
0.47
0.70
TRI
4:1
0
0.5
9.60
Excelsior Mat
6
0.13
0.08
0.05
0.55
0.56
0.93
4.50
0.47
0.70
TRI
4:1
0
0.5
9.60
Excelsior Mat
7
0.51
0.30
0.21
0.57
2.27
1.11
4.50
0.93
0.80
TRI
4:1
0
0.5
10.40
Excelsior Mat
8
0.61
0.36
0.25
0.57
2.71
2.50
4.50
1.50
0.75
TRI
4:1
1 0
0.5
10.00
Excelsior Mat
9
0.80
0.48
0.32
0.56
3.52
4.96
4.50
2.38
0.75
TRI
3:1
0
0.5
7.50
NC Green C125
10
0.15
0.09
0.06
0.56
0.66
1.11
4.50
0.49
0.50
TRI
4:1
0
0.5
8.80
Excelsior Mat
11
0.54
0.37
0.17
0.50
2.14
4.96
4.50
1.82
0.60
TRI
4:1
0
0.5
8.80
NC Green C125
12
2.97
2.12
0.85
0.59
11.33
1.14
4.50
2.02
1.30
TRI
4:1
0
0.5
14.40
NC Green C125
13
3.56
2.56
1.00
0.48
13.49
1.86
4.50
2.83
1.20
TRI
4:1
0
0.5
13.60
NC Green C125
14
1.91
1.23
0.68
0.53
7.97
2.10
4.50
2.20
0.96
TRI
4:1
0
0.5
11.68
Excelsior Mat
15
2.08
1.35
0.73
0.53
8.62
7.90
4.50
4.46
0.80
TRI
4:1
0
0.5
10.40
NC Green C125
16
2.19
1.401
0.79
0.53
9.19
4.20
4.50
3.41
0.86
TRI
4:1
0
0.5
10.88
NC Green C125BN
17
0.36
0.24
0.12
0.52
1.46
2.10
4.50
1.05
0.60
TRI
4:1
0
0.5
8.80
Excelsior Mat
18
0.57
0.41
0.16
0.48
2.16
7.90
4.50
2.17
0.55
TRI
4:1
0
0.5
8.40
NC Green C125
19
0.80
0.61
0.19
0.45
2.85
4.20
4.50
1.89
0.65
TRI
4:1
0
0.5
9.10
NC Green C125
20
7.52
5.10
2.42
0.51
24.05
1.86
4.50
3.41
1.35
TRI
4:1
0
0.5
14.80
NC Green C125
21
8.17
5.701
2.47
0.50
2.47
1.00
4.50
2.74
1.55
TRI
4:1
0
0.5
16.40
NC Green C125
22
0.09
0.05
0.04
0.66
0.47
8.75
4.50
1.35
0.30
TRI
4:1
0
1 0.5
8.80
Straw with net
PROVIDE 0.5' FREEBOARD MINIMUM. TOP WIDTH IS AT FREEBOARD
USE BERMUDA GRASS OR EQUAL
MAGNOLIA RIDGE SUBDIVISION - BUILT UPON AREA
Total Property Area =
Area below NHWL=
Total Project Area (TPA) _
Exist. Asphalt (EBUA)=
52.55 AC
2,289,078 SF
0 Ac
- SF
52.55 Ac
2,289,078 SF
0 AC - SF
DESCRIPTION
NO. LOTS
BUA (sf)
TOTAL BUA
sf
Proposed Roads Asphalt
103075
103,075
Proposed Lots BUA
82
5000
410,000
Mail kiosk & Parking
8,000
TOTAL BUA 521,075
15A NCAC 2H .1003(1): CALCULATION OF PROJECT DENSITY.
(b) A project with existing development may use the calculation method in Sub- Item (1)(a) or shall have
TYPICAL TRIANGULAR SWALE
1 "=20'
(1) TBUA - EBUA 521,075 - 521,075 sf
(2) TPA-EBUA = 2,289,078 - 2,289,078 sf
PROJECT
DENSITY = (1) / (2) 22.76%
Since the density is less than 24% it is a Low Density Project
SEE SWALE TABLE FOR DIMENSIONS AND LINER
THE GRASS SPECIES IN THE SWALE SHALL BE:
(A) NON -CLUMPING AND DEEP-ROOTED BERMUDA OR TALL FESCUE;
(B) ABLE TO WITHSTAND A VELOCITY OF FOUR FEET PER SECOND;
(C) MANAGED AT AN AVERAGE OF SIX INCHES; AND
(D) NOT BE CUT LOWER THAN FOUR INCHES.
(E) GRASS NEEDS TO BE WATERED FREQUENTLY FOR THE FIRST
THREE WEEKS AFTER PLANTING.
(F) IF GRASS IS NOT IN GOOD CONDITION, SOD WILL BE REQUIRED.
1 SWALE DETAILS
PLACE CONCRETE COLLAR 24" FROM
PIPE JOINT MIN
CAST IN PLACE CONCRETE TO BE 3,000
PSI @ 28 DAYS, REINFORCING STEEL TO
BE TRADE 60, FY10,000 PSI
7dIPP-► w-OA f
2 ANTI SEEP COLLAR
2'
BUA INCLUDES IIMPERVIOUS SURFACE AND PARTIALLY IMPERVIOUS
SURFACE TO THE EXTENT THAT THE PARTIALLY IMPERVIOUS
SURFACE DOES NOT ALLOW WATER TO INFILTRATE THROUGH THE
SURFACE AND INTO THE SUBSOIL: BUILDINGS, SIDEWALKS,
DRIVEWAYS.
"Built -upon area" does not include:
- a slatted deck;
- the water area of a swimming pool;
- a surface of number 57 stone, as designated by
the American Society for Testing and Materials, laid
at least four inches thick over a geotextile fabric;
- a trail as defined in G.S. 113A-85 that is either
unpaved or paved as long as the pavement is
porous with a hydraulic conductivity greater than
0.001 centimeters per second (1.41 inches per
hour); or
- landscaping material, including, but not limited to,
gravel, mulch, sand, and vegetation, placed on
areas that receive pedestrian or bicycle traffic or on
portions of driveways and parking areas that will not
be compacted by the weight of a vehicle, such aS
THE AREA BETWEEN SECTIONS OF
PAVEMENT THAT SUPPORT THE WEIGHT OF A
VEHICLE.
3/8/2022 4'
0.5FREEBOARD
2
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3/8/2022
TYPICAL TRAPEZOIDAL SWALE
1 "=20'
T�ASH RACK U ITH 4" TO 6" MAXIMUM OPENING SIZE 3/4" HINC
3" PLATE
i 16"
3/4" HINGE
#6 REBAR TYP.
3" ANGLE TYP
LOCK BOLT
ALL HARDWARE AND STRAPS USED TO ATTACH THE TRASH RACK SHALL
3/4" DOWEL LOCKING
3 TRASH RACK DETAIL
1
LtSJ 51 ttL
3/4" LOCK BOLT
8 TYPICAL
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FILE:
FOR AGENCY REVIEW 4-13-2022 ICP-202116-MAGNOLIA4-1